Form: S-1

General form for registration of securities under the Securities Act of 1933

May 20, 2026

Exhibit 1.1

[●] Shares

Deep Fission, Inc.

Common Stock, par value $0.0001 per share

Underwriting Agreement

[●], 2026

William Blair & Company, L.L.C.

Stifel, Nicolaus & Company, Incorporated

As representatives of the several Underwriters

named in Schedule I hereto,

c/o William Blair & Company, L.L.C.

150 North Riverside Plaza

Chicago, Illinois 60606

c/o Stifel, Nicolaus & Company, Incorporated

787 Seventh Avenue, 11th Floor
New York, New York 10019

Ladies and Gentlemen:

Deep Fission, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated in this Agreement (this “Agreement”), to issue and sell to the Underwriters named in Schedule I hereto (the “Underwriters”) for whom William Blair & Company, L.L.C. (“William Blair”) and Stifel, Nicolaus & Company, Incorporated (“Stifel”) are acting as representatives (the “Representatives” or “you”) an aggregate of [●] shares (the “Firm Securities”) and, at the election of the Underwriters, up to [●] additional shares (the “Optional Securities”) of common stock, par value $0.0001 per share (the “Common Stock”), of the Company (the Firm Securities and the Optional Securities that the Underwriters elect to purchase pursuant to Section 2 hereof are herein collectively called the “Securities”). To the extent that you are the only Underwriter, all references to “each Underwriter,” “the Underwriters” or “Representatives” shall refer to just you.

The Company understands that the Underwriters propose to make a public offering of their respective portions of the Securities as soon as you deem advisable.

William Blair has agreed to reserve a portion of the Securities to be purchased by it under this Agreement for sale to the Company’s officers, directors, employees and other parties related to the Company (collectively, “Participants”), as set forth in the Preliminary Prospectus and the Pricing Disclosure Package (each as defined herein) under the heading “Underwriting” (the “Directed Share Program”). The Securities to be sold by William Blair and its affiliates pursuant to the Directed Share Program, at the direction of the Company, are referred to hereinafter as the “Directed Shares.” Any Directed Shares not orally confirmed for purchase by any Participant by the end of the business day on which this Agreement is executed will be offered to the public by the Underwriters as set forth in the Preliminary Prospectus and the Pricing Disclosure Package.

1. The Company represents and warrants to, and agrees with, each of the Underwriters that:


(a) A registration statement on Form S-1 (File No. 333-[●]), including a prospectus, in respect of the Securities has been prepared by the Company and filed with the Securities and Exchange Commission (the “Commission”). Such registration statement, as of the time it became effective, including the amendments, exhibits and schedules thereto, including the Rule 430A Information (as defined below), is referred to herein at the “Registration Statement.” No stop order suspending the effectiveness of the Registration Statement, any post-effective amendment thereto or the Rule 462(b) Registration Statement (as defined below), if any, has been issued and no proceeding for that purpose has been initiated or, to the Company’s knowledge, threatened by the Commission. The Company will prepare and file a prospectus pursuant to Rule 424(b) of the rules and regulations of the Commission (the “Rules and Regulations”) that discloses the information previously omitted from the prospectus in the Registration Statement in reliance upon Rule 430A of the Rules and Regulations, which information will be deemed retroactively to be a part of the Registration Statement in accordance with Rule 430A of the Rules and Regulations (“Rule 430A Information”). If the Company has elected to rely upon Rule 462(b) of the Rules and Regulations to increase the size of the offering registered under the Securities Act of 1933, as amended (the “Act”), the Company will prepare and file with the Commission a registration statement with respect to such increase pursuant to Rule 462(b) of the Rules and Regulations (such registration statement the “Rule 462(b) Registration Statement”). Reference herein to the “Registration Statement” will be deemed to include the Rule 462(b) Registration Statement at and after the time of the filing of the Rule 462(b) Registration Statement. “Preliminary Prospectus” means any prospectus included in the Registration Statement prior to the effective time of the Registration Statement, any prospectus filed with the Commission pursuant to Rule 424(a) under the Rules and Regulations and each prospectus that omits Rule 430A Information used after the effective time of the Registration Statement; “Prospectus” means the form of the final prospectus filed with the Commission pursuant to Rule 424(b) under the Rules and Regulations that discloses the public offering price and other final terms of the Securities and the offering and otherwise satisfies Section 10(a) of the Act. All references in this Agreement to the Registration Statement, any Preliminary Prospectus, the Prospectus or any amendment or supplement to any of the foregoing, is deemed to include the copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System or any successor system thereto (“EDGAR”).

(b) No order preventing or suspending the use of the Preliminary Prospectus has been issued by the Commission, and each Preliminary Prospectus included in the Pricing Disclosure Package (as defined in Section 1(c) herein), at the time of filing thereof, conformed in all material respects to the requirements of the Act and the Rules and Regulations, and did not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information provided by any Underwriter through the Representatives is that identified as such in Section 9(b);

(c) For the purposes of this Agreement, the “Applicable Time” is [●] [a.m./p.m.] (New York City time) on the date of this Agreement. The Preliminary Prospectus, as supplemented by the information listed in Schedule II hereto (collectively, the “Pricing Disclosure Package”), as of the Applicable Time, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading;

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(d) From the time of initial confidential submission of the Registration Statement to the Commission (or, if earlier, the first date on which the Company engaged directly or through any person authorized to act on its behalf in any Testing-the-Waters Communication undertaken in reliance on Section 5(d) of the Act) through the date hereof, the Company has been and is an “emerging growth company,” as defined in Section 2(a) of the Act (an “Emerging Growth Company”). “Testing-the-Waters Communication” means any oral or written communication with potential investors that is undertaken in reliance on either Section 5(d) of, or Rule 163B under, the Act and is subject to the guidelines dated May 2026 as agreed to between the Underwriters and the Company.

(e) The Company (i) has not alone engaged in any Testing-the-Waters Communications other than Testing-the-Waters Communications with the consent of the Representatives (x) with entities that are qualified institutional buyers (“QIBs”) within the meaning of Rule 144A under the Act or institutions that are accredited investors within the meaning of Rule 501(a)(1), (a)(2), (a)(3), (a)(7) or (a)(8) under the Act (“IAIs”) and otherwise in compliance with the requirements of Section 5(d) of the Act or (y) with entities that the Company reasonably believed to be QIBs or IAIs and otherwise in compliance with the requirements of Rule 163B under the Act and (ii) has not authorized anyone other than the Underwriters to engage in Testing-the-Waters Communications. The Company has not distributed or approved for distribution any Written Testing-the-Waters Communications other than those listed on Schedule IV hereto. “Written Testing-the-Waters Communication” means any Testing-the-Waters Communication that is a written communication within the meaning of Rule 405 under the Act. Any individual Written Testing-the-Waters Communication does not conflict with the information contained in the Registration Statement or the Pricing Disclosure Package, complied in all material respects with the Act, and when taken together with the Pricing Disclosure Package as of the Applicable Time, did not, and as of the First Time of Delivery (as defined below) and as of each Subsequent Time of Delivery (as defined below), as the case may be, will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(f) The Registration Statement conforms, and the Prospectus and any further amendments or supplements to the Registration Statement and the Prospectus will conform, in all material respects to the requirements of the Act and the Rules and Regulations and do not and will not, as of the applicable effective date as to the Registration Statement and as of the applicable filing date as to the Prospectus and any amendment or supplement thereto, contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the case of the Prospectus, in light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information provided by any Underwriter through the Respresentatives is that identified as such in Section 9(b);

(g) From the time of initial confidential submission of the Registration Statement to the Commission through the date hereof, the Company has been and is a “smaller reporting company” as defined in Rule 12b-2 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) (“Smaller Reporting Company”).

(h) The financial statements of the Company (including all notes and schedules thereto) included in the Registration Statement, the Pricing Disclosure Package and the Prospectus comply with the applicable requirements of the Act and present fairly, in all material respects, the financial position of the Company and its subsidiary at the dates indicated, and the balance sheet, statement

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of operations, stockholders’ equity and cash flows of the Company and its subsidiary for the periods specified and such financial statements, and related schedules, if any, and notes thereto, have been prepared in conformity with generally accepted accounting principles in the United States (“GAAP”), consistently applied throughout the periods involved, except for any normal year-end adjustments in the Company’s quarterly financial statements; the supporting schedules, if any, present fairly in accordance with GAAP the information required to be stated therein; the summary financial information included in the Registration Statement, the Pricing Disclosure Package and the Prospectus present fairly, in all material respects, the information shown therein at the dates and for the periods specified and have been presented on a basis consistent with the audited financial statements included therein. No other financial statements or supporting schedules are required to be included in the Registration Statement, the Pricing Disclosure Package or the Prospectus. The other financial and related statistical information included in the Registration Statement, the Pricing Disclosure Package and the Prospectus presents fairly in all material respects the information included therein, in the case of financial information of the Company, has been derived from the accounting records of the Company. All disclosures, if any, contained in the Registration Statement and the Pricing Disclosure Package regarding “non-GAAP financial measures” (as such term is defined by the Rules and Regulations) comply, in all material respects, with Regulation G of the Exchange Act and Item 10 of Regulation S-K of the Act, to the extent applicable;

(i) The statistical and market-related data included in the Registration Statement and the Pricing Disclosure Package are based on or derived from sources that the Company believes to be reliable and accurate;

(j) Except as (i) described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, or (ii) would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect (as hereinafter defined), (A) the Company and its subsidiary have filed all United States federal, state, local and foreign income tax returns required by law to be filed through the date hereof and all taxes shown by such returns or otherwise assessed, which are due and payable, have been paid; and (B) there is no deficiency that has been, or could reasonably be expected to be, asserted against the Company or its subsidiary or any of their respective properties or assets other than tax deficiencies that the Company or its subsidiary are contesting in good faith and as to which adequate reserves have been established in accordance with GAAP;

(k) Neither the Company nor its subsidiary has sustained since the date of the latest audited financial statements included in the Registration Statement, the Pricing Disclosure Package and the Prospectus, any material loss or interference with its business, direct or contingent, including from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Registration Statement, the Pricing Disclosure Package and the Prospectus; and, since the respective dates as of which information is given in the Registration Statement, the Pricing Disclosure Package and the Prospectus, except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, there has not been (i) any change in the capital stock, short-term debt or long-term debt of the Company or its subsidiary, taken as a whole (other than changes pursuant to agreements or employee benefit plans or in connection with the exercise of options or warrants, in each case, as described or referred to in the Registration Statement, the Pricing Disclosure Package and the Prospectus), or any issuance of options, warrants, convertible securities or other rights to purchase the capital stock, of the Company or its subsidiary (other than issuances pursuant to agreements or employee benefit plans, in each case, as described or referred to in the Registration Statement, the Pricing Disclosure Package and the Prospectus), or (ii) any material adverse change, or any development involving a prospective material adverse change, in or affecting the properties,

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business, management, prospects, operations, earnings, assets, liabilities or condition (financial or otherwise) of the Company and its subsidiary, taken as a whole (a “Material Adverse Effect”);

(l) The Company and its subsidiary have good and marketable title to all real property owned by them and have good title to all other property owned by them, in each case free and clear of all liens, encumbrances and defects, except such as are described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, or such as do not materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Company and its subsidiary; and any real property and buildings held under lease by the Company and its subsidiary are held by them under valid, subsisting and enforceable leases, with such exceptions as are not material and do not materially interfere with the use made and proposed to be made of such property and buildings by the Company and its subsidiary;

(m) Except as disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus, neither the Company nor its subsidiary is in violation of any statute, any rule, regulation, decision or order of any federal, provincial, state, local, municipal, national or international government or governmental authority, regulatory or administrative agency, governmental commission, department, board, bureau, agency or instrumentality, court, tribunal, arbitrator or arbitral body (public or private), self-regulatory organization or any political subdivision of any of the foregoing (each, a “Governmental Authority”), relating to the use, disposal or release of hazardous or toxic substances or relating to the protection or restoration of the environment or human exposure to hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”), is liable pursuant to any Environmental Laws for any contamination by, or off-site disposal of, any substance or waste that is subject to regulation under Environmental Laws, or is subject to any claim relating to any Environmental Laws, which violation, contamination, liability or claim would, individually or in the aggregate, have a Material Adverse Effect; and the Company has not received notice of any actual or potential liability or obligation under or relating to, or any actual or potential violation of, any Environmental Laws, including for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants. The Company and its subsidiary have received all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses as currently conducted and are in compliance with all terms and conditions of any such permit, license or approval, except in each case where such noncompliance with Environmental Laws, failure to receive required permits, licenses or other approvals or failure to comply with the terms and conditions of such permits, licenses or approvals would not, individually or in the aggregate, have a Material Adverse Effect.

(n) Each of the Company and its subsidiary (i) has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, with corporate power and corporate authority to own its properties and conduct its business as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus and (ii) has been duly qualified as a foreign corporation for the transaction of business and is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification, except in the case of clause (ii), where the failure to be so qualified or in good standing would not have a Material Adverse Effect;

(o) The Company has full right, power and authority to execute and deliver this Agreement and to perform its obligations hereunder; and all action required to be taken for the due and proper authorization, execution and delivery by it of this Agreement and the consummation by it of the transactions contemplated hereby has been duly and validly taken;

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(p) This Agreement has been duly authorized, executed and delivered by the Company;

(q) The Company has an authorized capitalization as set forth in the Registration Statement, the Pricing Disclosure Package and the Prospectus under the caption “Description of Capital Stock” and all of the issued shares of capital stock of the Company have been duly authorized and validly issued and are fully paid and non-assessable and, with respect to shares of Common Stock, conform to the description of the Common Stock contained in the Registration Statement, the Pricing Disclosure Package and the Prospectus and all of the issued shares of capital stock of the subsidiary of the Company, if any, have been duly authorized and validly issued, are fully paid and non-assessable and are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims and there are no options, warrants or other rights to acquire shares of capital stock of the subsidiary of the Company; with respect to equity-based awards (the “Awards”) granted pursuant to the equity-based compensation plans of the Company (the “Company Stock Plans”), (i) each Award intended to qualify as an “incentive stock option” under Section 422 of the Internal Revenue Code so qualifies, (ii) each grant of an Award was duly authorized no later than the date on which the grant of such Award was by its terms to be effective (the “Grant Date”) by all necessary corporate action, including, as applicable, approval by the board of directors of the Company (the “Board of Directors”) (or a duly constituted and authorized committee thereof) and any required stockholder approval by the necessary number of votes or written consents, and the award agreement governing such grant (if any) was duly executed and delivered by each party thereto, (iii) each such grant was made in accordance with the terms of the Company Stock Plans, the Exchange Act and all other applicable laws and regulatory rules or requirements, (iv) the per share exercise price of each Award was equal to the fair market value of a share of Common Stock, as determined in good faith by the Board of Directors on the effective Grant Date and (v) each such grant was properly accounted for in accordance with GAAP, except, in each case, as would not have a Material Adverse Effect;

(r) The Securities to be issued and sold by the Company to the Underwriters hereunder have been duly authorized and, when issued and delivered against payment therefor as provided herein, will be duly and validly issued, fully paid and non-assessable and will conform to the description of the Securities contained in the Registration Statement, the Pricing Disclosure Package and the Prospectus; and the issuance of the Securities is not subject to any preemptive or similar rights that have not been waived or complied with;

(s) The execution, delivery and performance by the Company of this Agreement and the issue and sale of the Securities and the compliance by the Company with its obligations under this Agreement and the consummation of the transactions herein contemplated (i) will not conflict with or result in a material breach or violation of any of the terms or provisions of, or constitute a material default under, any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which the Company or its subsidiary is a party or by which the Company or its subsidiary is bound or to which any of the property or assets of the Company or its subsidiary is subject, (ii) will not violate any of the provisions of the Amended and Restated Certificate of Incorporation or Amended and Restated Bylaws of the Company, or the organizational documents of the subsidiary of the Company, (iii) will not violate any statute or any order, rule or regulation of any Governmental Authority having jurisdiction over the Company or its subsidiary or any of their properties, and (iv) will not require any consent, approval, authorization, order, registration or qualification of or with any Governmental Authority or third party, except for (x) such consents, approvals, authorizations, orders, registrations or qualifications that have been obtained or made and are in full force and effect, (y) the registration under the Act of the Securities and the approval by the Financial Industry Regulatory Authority, Inc. (“FINRA”) of the underwriting terms and arrangements and (z) such consents, approvals, authorizations, orders, registrations or qualifications

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as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Securities by the Underwriters;

(t) Neither the Company nor its subsidiary is (i) in violation of the Company’s Amended and Restated Certificate of Incorporation or Amended and Restated Bylaws or such subsidiary’s organizational documents, as applicable, or (ii) in default in the performance or observance of any obligation, agreement, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which it is a party or by which it or any of its properties may be bound, except, in the case of clause (ii), to the extent that such default would not have a Material Adverse Effect;

(u) The statements set forth in the Registration Statement, the Pricing Disclosure Package and Prospectus under the caption “Description of Capital Stock,” insofar as they purport to constitute a summary of the terms of the Common Stock, under the captions “Material U.S. Federal Tax Consequences to Non-U.S. Holders of Our Common Stock” and “Underwriting,” insofar as they purport to describe the provisions of the laws and documents referred to therein, and, to the extent they relate to or describe matters of law, regulation, governmental proceedings, the administration or enforcement thereof by any governmental authority, or the Company’s intellectual property, under the captions “Prospectus Summary—DOE Reactor Pilot Program and Development Activities,” “Risk Factors—Risks Related to Our Intellectual Property,” “Risk Factors—Risks Related to Our Regulatory Environment,” “Risk Factors—Our Gravity Reactor could experience a nuclear incident or otherwise cause environmental contamination, personal injuries or property damage, and reputational harm or losses not covered by indemnification or insurance could materially adversely affect our business,” “Business—Intellectual Property,” “Business—DOE Reactor Pilot Program and Development Activities” and “Business—Regulatory Matters,” insofar as they purport to describe a fair summary of the matters referred to therein, are accurate and complete in all material respects;

(v) Other than as set forth in the Registration Statement, the Pricing Disclosure Package and the Prospectus, there are no legal or governmental proceedings pending to which the Company or its subsidiary or, to the knowledge of the Company, any officer or director of the Company is a party or of which any property or assets of the Company or its subsidiary is the subject which would individually or in the aggregate reasonably be expected to have a Material Adverse Effect; and, to the Company’s knowledge, no such proceedings are threatened by any Governmental Authority or threatened by others. There are no statutes, regulations, legal or governmental proceedings required under the Act to be described in the Registration Statement, the Pricing Disclosure Package or the Prospectus that are not described in all material respects as required.

(w) The Company is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof, will not be required to register as an “investment company” or an entity “controlled” by an “investment company” as such terms are defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”);

(x) As of the date hereof, the Company is an “ineligible issuer,” as defined in Rule 405 under the Act, because of the Company’s or a predecessor’s status as a “shell company,” as defined in Rule 405 under the Act, within the past three years of the date hereof;

(y) Grant Thornton LLP, who have audited certain financial statements of the Company and its subsidiary, is an independent registered public accounting firm with respect to the Company as required by the Act and the Rules and Regulations and the Public Company Accounting Oversight Board (United States) (the “PCAOB”);

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(z) The Company maintains a system of internal control over financial reporting (as such term is defined in Rule 13a-15(f) under the Exchange Act) that complies with the requirements of the Exchange Act and has been designed by the Company’s principal executive officer and principal financial officer, or under their supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP. The Company and its subsidiary maintain internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any difference. Other than as set forth in the Registration Statement, the Pricing Disclosure Package and the Prospectus, the Company is not aware of any “significant deficiencies” or “material weaknesses” (each as defined by the PCAOB) in its internal control over financial reporting. The Company’s auditors and the Audit Committee of the Board of Directors have been advised of: (i) all significant deficiencies and material weaknesses in the design or operation of internal controls over financial reporting which have adversely affected or are reasonably likely to adversely affect the Company’s ability to record, process, summarize and report financial information; and (ii) any fraud, whether or not material, that involves management or other employees who have a significant role in the Company’s internal controls over financial reporting;

(aa) The interactive data in eXtensible Business Reporting Language included in the Registration Statement fairly presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines applicable thereto.

(bb) Since the date of the latest audited financial statements included in the Registration Statement, the Pricing Disclosure Package and the Prospectus, there has been no change in the Company’s internal control over financial reporting that has materially adversely affected, or is reasonably likely to materially adversely affect, the Company’s internal control over financial reporting;

(cc) The Company maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) under the Exchange Act) that comply with the requirements of the Exchange Act; such disclosure controls and procedures have been designed to ensure that material information relating to the Company and its subsidiary is made known to the Company’s principal executive officer and principal financial officer by others within those entities; and other than as set forth in the Registration Statement, the Pricing Disclosure Package and the Prospectus, such disclosure controls and procedures are effective;

(dd) Except (i) as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, or (ii) as would not, individually or in the aggregate, result in a Material Adverse Effect, the Company or its subsidiary owns, possesses, or can acquire on reasonable terms, all Intellectual Property (as defined below) necessary for the conduct of the Company’s or its subsidiary’s business as now conducted or as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus to be conducted, and there are no unreleased liens or security interests which have been filed against any of the patents owned by the Company or its subsidiary. Furthermore, except as would not, individually or in the aggregate, result in a Material Adverse Effect, (i) to the knowledge of the Company, there is no infringement, misappropriation or violation by third parties of any such Intellectual Property; (ii) there is no pending or, to the

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knowledge of the Company, threatened, action, suit, proceeding or claim by others challenging the Company’s or its subsidiary’s rights in or to any such Intellectual Property and the Company is unaware of any facts which would form a reasonable basis for any such claim; (iii) the Intellectual Property owned by the Company or its subsidiary, and to the knowledge of the Company, the Intellectual Property licensed to the Company or its subsidiary, has not been adjudged invalid or unenforceable, in whole or in part, and there is no pending or, to the knowledge of the Company, threatened action, suit, proceeding or claim by others challenging the validity or scope of any such Intellectual Property and the Company is not aware of any facts which would form a reasonable basis for any such claim; (iv) there is no pending or, to the knowledge of the Company, threatened action, suit, proceeding or claim by others that the Company or its subsidiary infringes, misappropriates or otherwise violates any Intellectual Property or other proprietary rights of others, neither the Company nor its subsidiary has received any written notice of such claim and the Company is unaware of any other fact which would form a reasonable basis for any such claim; (v) the Company and its subsidiary have complied with the terms of each agreement pursuant to which Intellectual Property has been licensed to the Company or its subsidiary, and all such agreements are in full force and effect; (vi) the product candidates described in the Registration Statement, the Pricing Disclosure Package and the Prospectus as under development by the Company or its subsidiary fall within the scope of the claims of one or more patents or applications relating to the product candidate or its intended use owned by, or exclusively licensed to, the Company or its subsidiary; and (vii) to the Company’s knowledge, no employee of the Company or its subsidiary is in or has ever been in violation of any term of any employment contract, patent disclosure agreement, invention assignment agreement, non-competition agreement, non-solicitation agreement, nondisclosure agreement or any restrictive covenant to or with a former employer where the basis of such violation relates to such employee’s employment with the Company or its subsidiary or actions undertaken by the employee while employed with the Company or its subsidiary. “Intellectual Property” shall mean all patents, patent applications, trade and service marks, trade and service mark registrations, trade names, copyrights, licenses, inventions, trade secrets, domain names, technology, know-how and other intellectual property;

(ee) There are no off-balance sheet arrangements that may have a material current or future effect on the Company’s financial condition, changes in financial condition, results of operations, liquidity, capital expenditures or capital resources;

(ff) Each of the Company and its subsidiary have complied, and are presently in compliance, in all material respects, with its privacy and security policies, and with all applicable laws and regulations regarding the collection, use, transfer, storage, protection, disposal and/or disclosure of personally identifiable information (collectively, the “Data Protection Requirements”). To ensure compliance with the Data Protection Requirements, the Company and its subsidiary have in place, comply with, and take appropriate steps reasonably designed to ensure compliance in all material respects with their policies and procedures relating to data privacy and security and the collection, storage, use, disclosure, handling, and analysis of personally identifiable information (the “Policies”). The Company and its subsidiary have at all times made all disclosures to users or customers required by applicable Data Protection Requirements, and none of such disclosures made or contained in any Policy have, to the knowledge of the Company, been inaccurate or in violation of any applicable Data Protection Requirements in any material respect. Except as would not reasonably be expected to have a Material Adverse Effect, neither the Company nor its subsidiary: (i) has received notice of any actual or potential liability under or relating to, or actual or potential violation of, any of the Data Protection Requirements, and has no knowledge of any event or condition that would reasonably be expected to result in any such notice; (ii) is currently conducting or paying for, in whole or in part, any investigation, remediation, or other corrective action pursuant to any Data Protection

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Requirement; or (iii) is a party to any order, decree, or agreement that imposes any obligation or liability by any governmental or regulatory authority under any Data Protection Requirement. The execution, delivery and performance of this Agreement or any other agreement referred to in this Agreement will not result in a breach of any Policies;

(gg) The Company and its subsidiary are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are, in the Company’s reasonable judgment, prudent and customary in the businesses in which they are engaged; neither the Company nor its subsidiary has been refused any insurance coverage sought or applied for; and neither the Company nor its subsidiary has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not have a Material Adverse Effect;

(hh) There are no contracts or other documents which are required to be described in the Registration Statement, the Pricing Disclosure Package or the Prospectus or to be filed as an exhibit to the Registration Statement which have not been described in all material respects or filed as required;

(ii) Except as disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus, there are no related party transactions that would be required to be disclosed therein by Item 404 of Regulation S-K promulgated under the Act and any such related party transactions described therein are accurately described in all material respects;

(jj) Except (i) as set forth or described in the Registration Statement, the Pricing Disclosure Package and the Prospectus or (ii) as would not have, individually or in the aggregate, a Material Adverse Effect, none of the following events has occurred or exists: (A) a failure to fulfill the obligations, if any, under the minimum funding standards of Section 302 of the United States Employee Retirement Income Security Act of 1974, as amended (“ERISA”), and the regulations and published interpretations thereunder with respect to a Plan, determined without regard to any waiver of such obligations or extension of any amortization period; (B) to the knowledge of the Company, an audit or investigation by the Internal Revenue Service, the U.S. Department of Labor, the Pension Benefit Guaranty Corporation or any Governmental Authority with respect to the employment or compensation of employees by any of the Company or its subsidiary; or (C) any breach of any contractual obligation, or any violation of law or applicable qualification standards, with respect to the employment or compensation of employees by the Company or its subsidiary. Except (i) as set forth or described in the Registration Statement, the Pricing Disclosure Package and the Prospectus or (ii) as would not have, individually or in the aggregate, a Material Adverse Effect, none of the following events has occurred or is reasonably likely to occur: (A) an increase in the aggregate amount of contributions required to be made to all Plans in the current fiscal year of the Company and its subsidiary compared to the amount of such contributions made in the most recently completed fiscal year of the Company and its subsidiary; (B) an increase in the “accumulated post-retirement benefit obligations” (within the meaning of Statement of Financial Accounting Standards 106) of the Company and its subsidiary compared to the amount of such obligations in the most recently completed fiscal year of the Company and its subsidiary; (C) any event or condition giving rise to a liability under Title IV of ERISA; or (D) the filing of a material claim by one or more employees or former employees of the Company or its subsidiary related to their employment. For purposes of this paragraph, the term “Plan” means a plan (within the meaning of Section 3(3) of ERISA) with respect to which the Company or its subsidiary may have any liability;

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(kk) Except as would not have a Material Adverse Effect, the operations of the Company and its subsidiary are and have been conducted at all times in compliance with ERISA, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any Governmental Authority (collectively, the “Employee Benefit Laws”) and no action, suit or proceeding by or before any Governmental Authority to which the Company or its subsidiary is a party with respect to the Employee Benefit Laws is pending or, to the knowledge of the Company, threatened;

(ll) There are no contracts, agreements or understandings between the Company or its subsidiary and any person (other than this Agreement) that would give rise to a valid claim against the Company or any Underwriter for a brokerage commission, finder’s fee or other like payment in connection with the offering of the Securities;

(mm) None of the outstanding shares of Common Stock were issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase securities of the Company; there are no persons with registration or other similar rights to have securities of the Company registered under the Act other than as disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus; and there are no persons with registration or similar rights that would require any securities of the Company to be included in the Registration Statement or in the offering contemplated hereby; there are no authorized or outstanding options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company or its subsidiary other than those described in the Registration Statement, the Pricing Disclosure Package and the Prospectus or those issued or issuable under the Company Stock Plans described in the Registration Statement, the Pricing Disclosure Package and the Prospectus; and the description of the Company’s stock option, stock bonus and other stock plans or arrangements, and the options or other rights granted thereunder, included in the Registration Statement, the Pricing Disclosure Package and the Prospectus fairly presents in all material respects the information required to be shown with respect to such plans, arrangements, options and rights;

(nn) (i) Neither the Company nor its subsidiary, nor any of their directors or officers, nor, to the Company’s knowledge, any employee, agent, affiliate or representative of the Company or its subsidiary, is an individual or entity that is, or is owned or controlled by an individual or entity that is (A) the subject of any sanctions administered or enforced by the U.S. Department of Treasury’s Office of Foreign Assets Control, the United Nations Security Council, the European Union, His Majesty’s Treasury or other relevant sanctions authority (collectively, “Sanctions”), nor (B) located, organized or resident in a country or territory that is the subject of Sanctions (including, without limitation, the so-called Donetsk People’s Republic, the so-called Luhansk People’s Republic, the Crimea region of Ukraine, Cuba, Iran, and North Korea); (ii) neither the Company nor its subsidiary will, directly or indirectly, use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other individual or entity (A) to fund or facilitate any activities or business of or with any individual or entity or in any country or territory that, at the time of such funding or facilitation, is the subject of Sanctions; or (B) in any other manner that will result in a violation of Sanctions by any individual or entity (including any individual or entity participating in the offering, whether as underwriter, advisor, investor or otherwise); (iii) for the past five years, neither the Company nor its subsidiary has knowingly engaged in, and is not now knowingly engaged in, any dealings or transactions with any individual or entity, or in any country or territory, that at the time of the dealing or transaction is or was the subject of Sanctions;

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(oo) The operations of the Company and its subsidiary are and have been conducted at all times in compliance with applicable federal, state, international, foreign or other laws, regulations or government guidance regarding financial record-keeping and reporting requirements, including, without limitation, Title 18 U.S. Code Section 1956 and 1957, the Bank Secrecy Act, as amended by Title III of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT Act), the Currency and Foreign Transactions Reporting Act of 1970, as amended, the applicable money laundering statutes of jurisdictions where the Company and the subsidiary conduct business, the applicable rules and regulations thereunder, and international anti-money laundering principles or procedures by an intergovernmental group or organization, such as the Financial Action Task Force on Money Laundering, of which the United States is a member and with which designation the United States representative to the group or organization continues to concur, all as amended, and any Executive order, directive or regulation pursuant to the authority of any of the foregoing, or any orders or licenses issued thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any Governmental Authority (collectively, the “Money Laundering Laws”), and no action, suit or proceeding by or before any Governmental Authority involving the Company or its subsidiary with respect to the Money Laundering Laws is pending or, to the knowledge of the Company, threatened;

(pp) Neither the Company nor its subsidiary, nor any director, officer or employee of the Company or its subsidiary, nor, to the Company’s knowledge, any agent, affiliate or other person associated with or acting on behalf of the Company or its subsidiary, is aware of or has, directly or indirectly, (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made or taken an act in furtherance of an offer, promise or authorization of any direct or indirect unlawful payment or benefit to any foreign or domestic government official or employee, including any government-owned or controlled entity or of a public international organization, or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office; (iii) made or taken any action that would result in a violation by such persons of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”) or any applicable law or regulation implementing the OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions, or committed an offence under the Bribery Act 2010 of the United Kingdom or any other applicable anti-bribery or anti-corruption law, including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and (iv) made, offered, agreed, requested or taken an act in furtherance of any unlawful bribe or other unlawful benefit, including, without limitation, any rebate, payoff, influence payment, kickback or other unlawful or improper payment or benefit. The Company, its subsidiary and, to the Company’s knowledge, its affiliates have conducted their businesses in compliance with the FCPA and all other applicable anti-bribery and anti-corruption laws and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith;

(qq) The Company and its subsidiary possess all certificates, authorizations and permits issued by the appropriate federal, state or foreign regulatory authorities necessary to conduct their respective businesses, and neither the Company nor its subsidiary has received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit, except for such failures to possess or such notices that, individually or in the aggregate, would

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not reasonably be expected to have a Material Adverse Effect, except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus;

(rr) The Company, and each of the Company’s directors and officers, in their capacities as such, to the Company’s knowledge, is in compliance with all applicable provisions of the Sarbanes-Oxley Act of 2002, as amended, and the Rules and Regulations (the “Sarbanes-Oxley Act”), including Section 402 related to loans and Sections 302 and 906 related to certifications; it being understood that nothing in this Agreement requires the Company to comply with Section 404 of the Sarbanes-Oxley Act as of an earlier date than it would otherwise be required to do so under applicable law;

(ss) Except as would not, individually or in the aggregate, result in a Material Adverse Effect, the Company, or its subsidiary, is not a party to and does not have any ongoing reporting obligations pursuant to any corporate integrity agreements, monitoring agreements, deferred prosecution agreements, consent decrees, settlement orders, plan of correction or similar agreements with or imposed by any Governmental Authority;

(tt) No relationship, direct or indirect, exists between or among the Company or its subsidiary, on the one hand, and the directors, officers, stockholders, customers or suppliers of the Company or its subsidiary, on the other, that is required by the Act to be described in the Registration Statement, the Pricing Disclosure Package and the Prospectus and that is not so described in all material respects in such documents;

(uu) (i) Except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, there has been no security breach or incident, unauthorized access or disclosure, or other compromise of or relating to the Company’s or its subsidiary’s information technology and computer systems, networks, hardware, software, data and databases (including the data and information of their respective customers, employees, suppliers, vendors and any third-party data maintained, processed or stored by the Company and its subsidiary, and any such data processed or stored by third parties on behalf of the Company and its subsidiary), equipment or technology (collectively, “IT Systems and Data”), except for those that have been remedied without material cost or liability or those that would not reasonably be expected to be material to the Company and its subsidiary, taken as a whole; (ii) except as has not been, would not reasonably be expected to be, material to the Company and its subsidiary, taken as a whole, neither the Company nor its subsidiary have been notified of, and have no knowledge of any event or condition that would reasonably be expected to result in, any security breach or incident, unauthorized access or disclosure or other compromise to their IT Systems and Data; and (iii) the Company and its subsidiary, taken as a whole, have implemented commercially reasonable controls, policies, procedures and technological safeguards to maintain and protect the integrity, continuous operation, redundancy and security of their IT Systems and Data reasonably consistent with industry standards and practices, or as required by applicable regulatory standards. The Company and its subsidiary are presently in compliance with all applicable laws or statutes and all applicable judgments, orders, rules and regulations of any Governmental Authority, and the Company’s and its subsidiary’s public-facing policies and contractual obligations, in each case, relating to the privacy and security of IT Systems and Data and to the protection of such IT Systems and Data from unauthorized use, access, misappropriation or modification, except in each case as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect;

(vv) Except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, the Company has not sold, issued or distributed any shares of Common Stock during the six month period preceding the date hereof, including any sales pursuant to Rule 144A under, or Regulation D or S of, the Act, other than shares issued pursuant to Company Stock Plans;

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(ww) There are no debt securities, convertible securities or preferred stock issued, or guaranteed by, the Company or its subsidiary that are rated by a “nationally recognized statistical rating organization,” as such term is defined in Section 3(a)(62) of the Exchange Act;

(xx) The subsidiary of the Company is not currently prohibited, directly or indirectly, under any agreement or other instrument to which it is a party or is subject, from paying any dividends to the Company, from making any other distribution on the subsidiary’s capital stock or similar ownership interest, from repaying to the Company any loans or advances to the subsidiary from the Company or from transferring any of the subsidiary’s properties or assets to the Company;

(yy) Neither the Company nor its subsidiary or affiliates has taken, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities;

(zz) Neither the issuance, sale and delivery of the Securities nor the application of the proceeds thereof by the Company as described in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus will violate Regulation T, U or X of the Board of Governors of the Federal Reserve System or any other regulation of such Board of Governors;

(aaa) No forward-looking statement (within the meaning of Section 27A of the Act and Section 21E of the Exchange Act) included in any of the Registration Statement, the Pricing Disclosure Package or the Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith;

(bbb) Except as disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus, the Company (i) does not have any material lending or other relationship with any bank or lending affiliate of any Underwriter and (ii) does not intend to use any of the proceeds from the sale of the Securities to repay any outstanding debt owed to any affiliate of any Underwriter;

(ccc) Except as would not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect, no strike, slowdown, stoppage or any other labor dispute exists with the employees of the Company or its subsidiary, or, to the knowledge of the Company, is any such strike, slowdown, stoppage or dispute imminent; and the Company is not aware of any existing, threatened or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers or contractors that would reasonably be expected to have a Material Adverse Effect;

(ddd) Neither the Company nor its subsidiary is a “covered foreign person,” as that term is used in the Outbound Investment Rules. Neither the Company nor its subsidiary currently engages, or has any present intention to engage in the future, directly or indirectly, in (i) a “covered activity” or a “covered transaction”, as each such term is defined in the Outbound Investment Rules or (ii) any activity or transaction that would constitute a “covered activity” or a “covered transaction”, as each such term is defined in the Outbound Investment Rules. “Outbound Investment Rules” means the regulations administered and enforced, together with any related public guidance issued, by the United States Treasury Department under U.S. Executive Order 14105 or any similar law or regulation; as of the date of this Agreement, the Outbound Investment Rules are codified at 31 C.F.R. § 850.101 et seq.;

(eee) The Registration Statement, the Pricing Disclosure Package, the Prospectus and any Preliminary Prospectus comply, and any amendments or supplements thereto will comply in all material respects, with any applicable laws or regulations of foreign jurisdictions in which the Pricing Disclosure Package, the Prospectus and any Preliminary Prospectus, as amended or supplemented, if applicable, are distributed in connection with the Directed Share Program;

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(fff) No consent, approval, authorization or order of, or qualification with, any governmental body or agency, other than those obtained, is required in connection with the offering of the Directed Shares in any jurisdiction where the Directed Shares are being offered; and

(ggg) The Company has not offered, or caused William Blair or each person, if any, who controls William Blair within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act and each affiliate of William Blair within the meaning of Rule 405 of the Securities Act to offer, Shares to any person pursuant to the Directed Share Program with the specific intent to unlawfully influence (i) a customer or supplier of the Company to alter the customer’s or supplier’s level or type of business with the Company, or (ii) a trade journalist or publication to write or publish favorable information about the Company or its products.

2. Subject to the terms and conditions herein set forth, (a) the Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price per share of $[●], the number of Firm Securities set forth opposite the name of such Underwriter in Schedule I hereto and (b) in the event and to the extent that the Underwriters shall exercise the election to purchase Optional Securities as provided below, the Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at the purchase price per share set forth in clause (a) of this Section 2, that portion of the number of Optional Securities as to which such election shall have been exercised (to be adjusted by you so as to eliminate fractional shares) determined by multiplying such number of Optional Securities by a fraction, the numerator of which is the maximum number of Optional Securities which such Underwriter is entitled to purchase as set forth opposite the name of such Underwriter in Schedule I hereto (or such number increased as set forth in Section 12 hereof) and the denominator of which is the maximum number of Optional Securities that all of the Underwriters are entitled to purchase hereunder.

The Company hereby grants to the Underwriters the right to purchase at their election and solely to cover over-allotments, at any time in whole, or from time to time in part, up to [●] Optional Securities, at the purchase price per share set forth in the paragraph above, provided that the purchase price per Optional Share shall be reduced by an amount per share equal to any dividends or distributions declared by the Company and payable on the Firm Securities but not payable on the Optional Securities. Any such election to purchase Optional Securities may be exercised only by written notice from you to the Company, given within a period of 30 calendar days after the date of this Agreement, setting forth the aggregate number of Optional Securities to be purchased and the date on which such Optional Securities are to be delivered, as determined by you but in no event earlier than the First Time of Delivery (as defined in Section 4 hereof) or, unless you and the Company otherwise agree in writing, earlier than two or later than ten business days after the date of such notice.

3. Upon the authorization by you of the release of the Firm Securities, the several Underwriters propose to offer the Firm Securities for sale upon the terms and conditions set forth in the Prospectus.

4. (a) The Securities to be purchased by each Underwriter hereunder, in definitive form, and in such authorized denominations and registered in such names as the Representatives may request upon at least forty-eight hours’ prior notice to the Company shall be delivered by or on behalf of the Company to the Representatives, through the facilities of the Depository Trust Company (“DTC”), for the account of such Underwriter, against payment by or on behalf of such Underwriter of the purchase price therefor by wire transfer of Federal (same-day) funds to the account specified by the Company to the Representatives at least forty-eight hours in advance. The time and date of such delivery and payment shall be, with respect to the Firm Securities, 9:30 a.m., New York City time, on

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[●], 2026 or such other time and date as the Representatives and the Company may agree upon in writing, and, with respect to the Optional Securities, 9:30 a.m., New York City time, on the date specified by the Representatives in the written notice given by the Representatives of the Underwriters’ election to purchase such Optional Securities, or such other time and date as the Representatives and the Company may agree upon in writing. Such time and date for delivery of the Firm Securities is herein called the “First Time of Delivery”, such times and dates for delivery of the Optional Securities, if not the First Time of Delivery, are each herein called a “Subsequent Time of Delivery”, and each such time and date for delivery is herein called a “Time of Delivery”.

(b) The documents to be delivered at each Time of Delivery by or on behalf of the parties hereto pursuant to Section 8 hereof, including the cross-receipt for the Securities and any additional documents requested by the Underwriters pursuant to Section 8(m) hereof, will be delivered at the offices of Latham & Watkins LLP at 330 North Wabash Avenue, Suite 2800, Chicago, Illinois 60611 (the “Closing Location”), and the Securities will be delivered at the office of DTC (or its designated custodian), all at such Time of Delivery. At 5:00 p.m., New York City time, on the New York Business Day immediately preceding such Time of Delivery, the final drafts of the documents to be delivered pursuant to the preceding sentence will be available virtually for review by the parties hereto.

5. The Company agrees with each of the Underwriters:

(a) To prepare the Prospectus in a form approved by you and to file such Prospectus pursuant to Rule 424(b) under the Act not later than the Commission’s close of business on the second business day following the execution and delivery of this Agreement or such earlier time as may be required under the Act; to notify you promptly if the Company intends to make any further amendment or any supplement to the Registration Statement, the Preliminary Prospectus or the Prospectus prior to the last Time of Delivery and to make no amendment or supplement to the Registration Statement, the Preliminary Prospectus or the Prospectus without providing you with a reasonable time to review and comment upon such filing; to advise you, promptly after it receives notice thereof, of the time when any amendment to the Registration Statement has been filed or becomes effective or any amendment or supplement to the Prospectus has been filed, in each case prior to the last Time of Delivery, and to furnish you with copies thereof; to file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of the Prospectus and for so long as the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is required in connection with the offering or sale of the Securities; to advise you, promptly after it receives notice thereof, prior to the last Time of Delivery, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of any prospectus in respect of the Securities, of the suspension of the qualification of the Securities for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose, or of any request by the Commission for the amending or supplementing of the Registration Statement or the Prospectus or for additional information; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of any prospectus in respect of the Securities or suspending any such qualification, to promptly use its best efforts to obtain the withdrawal of such order;

(b) Promptly from time to time to take such action as you may reasonably request to qualify the Securities for offering and sale under the securities laws of such jurisdictions as you may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Securities, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation or

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to file a general consent to service of process in any jurisdiction or subject itself to taxation in any jurisdiction in which it is not otherwise subject to taxation on the date hereof;

(c) Prior to 10:00 a.m., New York City time, on the New York Business Day next succeeding the date of this Agreement and from time to time, to furnish the Underwriters with written and electronic copies of the Prospectus in New York City in such quantities as you may reasonably request, and, if the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is required at any time prior to the expiration of nine months after the time of issue of the Prospectus in connection with the offering or sale of the Securities, and if you have notified the Company that the delivery of a prospectus is required after the last Time of Delivery, and if at such time any event shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances then prevailing when such Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is delivered, not misleading, or, if for any other reason it shall be necessary during such same period to amend or supplement the Prospectus in order to comply with the Act or the Exchange Act, to notify you and upon your request to file such document and to prepare and furnish without charge to each Underwriter and to any dealer in securities as many written and electronic copies as you may from time to time reasonably request of an amended Prospectus or a supplement to the Pricing Disclosure Package or Prospectus which will correct such statement or omission or effect such compliance; and in case any Underwriter is required to deliver a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) in connection with sales of any of the Securities at any time nine months or more after the time of issue of the Prospectus, upon your request but at the expense of such Underwriter, to prepare and deliver to such Underwriter as many written and electronic copies as you may request of an amended or supplemented Prospectus complying with Section 10(a)(3) of the Act;

(d) To make generally available to its securityholders as soon as practicable, but in any event not later than sixteen months after the effective date of the Registration Statement (as defined in Rule 158(c) under the Act), an earnings statement of the Company and its subsidiary (which need not be audited) complying with Section 11(a) of the Act and the Rules and Regulations (including, at the option of the Company, Rule 158);

(e) During the period beginning from the date hereof and continuing to the close of business on the date that is 180 days after the date of the Prospectus (the “Lock-Up Period”), not to (i) offer, sell, contract to sell, pledge, sell any option or grant any option, right or warrant to purchase, lend, make any short sale or otherwise transfer or dispose of, directly or indirectly, or submit or file with the Commission a registration statement under the Act relating to, any securities of the Company that are substantially similar to the Securities, including but not limited to any options or warrants to purchase shares of Common Stock or any securities that are convertible into or exchangeable for, or that represent the right to receive, Common Stock, or any such substantially similar securities, or publicly disclose the intention to make any offer, sale, pledge, disposition or filing or (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the Common Stock, or any such other securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise, without the prior written consent of William Blair, in each case, other than (A) the Securities to be sold to the Underwriters hereunder, (B) the issuance of options, stock awards, restricted stock, restricted stock units, warrants or other equity awards to acquire shares of Common Stock granted pursuant to the Company Stock Plans in effect at the Time of Delivery that are described in the Prospectus, as such plans may be amended, (C) the issuance of shares of Common Stock upon the exercise, vesting or settlement of any such options, warrants or other equity awards

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to acquire shares of Common Stock, (D) shares of Common Stock issued upon exercise of outstanding warrants, (E) the filing of one or more Registration Statements (or amendments to existing Registration Statements) pursuant to the Company’s obligations under its registration rights agreements with stockholders in effect at the Time of Delivery that are described in the Prospectus; (F) the filing of one or more Registration Statements on Form S-8 registering securities pursuant to the Company Stock Plans; (G) facilitating the establishment of a trading plan on behalf of a shareholder, officer or director of the Company pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Common Stock, provided that (x) such plan does not provide for the transfer of Common Stock during the Lock-Up Period and (y) to the extent a public announcement or filing under the Exchange Act, if any, is required of or voluntarily made by the Company regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of Common Stock may be made under such plan during the Lock-Up Period, (H) the confidential submission to the Commission or FINRA of any registration statement under the Securities Act, provided, however, that no public announcement is made during the Lock-Up Period regarding such submission and (I) the issuance of shares of Common Stock or any securities that are convertible into or exchangeable for, or that represent the right to receive, Common Stock (in an amount not to exceed 7.5% of the outstanding Common Stock on a fully diluted basis immediately following the transactions contemplated by this Agreement) in any private placement, including in connection with any commercialization, joint venture, acquisition of complementary businesses, products, services or technologies, development collaboration, mergers, acquisitions or other similar strategic transactions, provided that such recipients enter into a lock-up agreement with the Company (which the Company may not waive without the consent of William Blair) with respect to the remaining portion of the Lock-Up Period and any registration rights of such recipient are not exercisable until after the Lock-Up Period.

If William Blair, in its sole discretion, agrees to release or waive the restrictions set forth in a lock-up letter described in Section 8(i) hereof for an officer or director of the Company and provides the Company with notice of the impending release or waiver substantially in the form of Annex II hereto at least three business days before the effective date of the release or waiver, the Company agrees to announce the impending release or waiver substantially in the form of Annex III hereto through a major news service at least two business days before the effective date of the release or waiver.

(f) If the Company elects to rely upon Rule 462(b), the Company shall file a Rule 462(b) Registration Statement with the Commission in compliance with Rule 462(b) by 10:00 p.m., Washington, D.C. time, on the date of this Agreement, and the Company shall at the time of filing either pay the Commission the filing fee for the Rule 462(b) Registration Statement or give irrevocable instructions for the payment of such fee pursuant to Rule 111(b) under the Act;

(g) To use the net proceeds received by it from the sale of the Securities pursuant to this Agreement in the manner specified in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus under the caption “Use of Proceeds”;

(h) To use its best efforts to list, subject to notice of issuance, the Securities on the Nasdaq Global Market;

(i) [reserved];

(j) To comply with all applicable securities and other laws, rules and regulations in each jurisdiction in which the Directed Shares are offered in connection with the Directed Share Program;

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(k) Neither the Company nor its subsidiary or affiliates will take, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities;

(l) So long as the Securities are outstanding, the Company will furnish to the Representatives, as soon as they are available, copies of all reports or other communications (financial or other) furnished to holders of the Securities, and copies of any reports and financial statements furnished to or filed with the Commission or any national securities exchange or automatic quotation system; provided the Company will be deemed to have furnished such reports and financial statements to the Representatives to the extent they are filed on EDGAR; and

(m) The Company will promptly notify the Representatives if the Company ceases to be an Emerging Growth Company or a Smaller Reporting Company at any time prior to the completion of the distribution of Securities within the meaning of the Act.

6. The Company represents and agrees that, without the prior consent of the Representatives, it has not made and will not make any offer relating to the Securities that would constitute a “free writing prospectus” as defined in Rule 405 under the Act or any Written Testing-the-Waters Communication, other than any Written Testing-the-Waters Communication the use of which has been consented to by the Representatives and which is listed on Schedule IV hereto; each Underwriter represents and agrees that, without the prior consent of the Company and the Representatives, it has not made and will not make any offer relating to the Securities that would constitute a free writing prospectus.

7. Whether or not the transactions contemplated by this Agreement are consummated or this Agreement is terminated, the Company covenants and agrees with the several Underwriters that the Company will pay or cause to be paid the following: (i) the fees, disbursements and expenses of the Company’s counsel and accountants in connection with the registration of the Securities under the Act and all other expenses of the Company in connection with the preparation, printing, reproduction and filing of the Registration Statement, the Preliminary Prospectus, the Pricing Disclosure Package and the Prospectus and any amendments or supplements thereto and the mailing and delivering of copies thereof to the Underwriters and dealers; (ii) the cost of printing or producing any Agreement among Underwriters, this Agreement, the Blue Sky survey, closing documents (including any compilations thereof) and any other documents in connection with the offering, purchase, sale and delivery of the Securities; (iii) all expenses in connection with the qualification of the Securities for offering and sale under state securities laws, including the reasonable and documented fees and disbursements of counsel for the Underwriters in connection with such qualification and in connection with the Blue Sky survey; (iv) all fees and expenses in connection with listing the Securities on the Nasdaq Global Market; (v) the filing fees incident to, and the reasonable and documented fees and disbursements of counsel for the Underwriters in connection with, any required review by FINRA of the terms of the sale of the Securities; (vi) the cost of preparing stock certificates, if applicable; (vii) the cost and charges of any transfer agent or registrar; (viii) the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the Securities, including without limitation, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged by the Company in connection with the road show presentations, travel and lodging expenses of the representatives and officers of the Company and any such consultants in connection with the roadshow, (ix) 50% of transportation costs of the Underwriters in connection with the road show; provided that travel expenses shall be limited to economy class (or equivalent) and that the Underwriters will use commercially reasonable efforts to minimize such expenses; (x) the costs and

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expenses of the Underwriters, including documented fees and disbursements of counsel for the Underwriters; (xi) all fees and disbursements of counsel incurred by the Underwriters in connection with the Directed Share Program and stamp duties, similar taxes or duties or other taxes, if any, incurred by the Underwriters in connection with the Directed Share Program, and (xii) all other costs and expenses incident to the performance of its obligations hereunder which are not otherwise specifically provided for in this Section 7; provided that in no event shall the Company be obligated to pay, or cause to be paid, more than $200,000 in the aggregate for all fees and disbursements of counsel under clauses (iii) and (v) and all costs and expenses (including fees and disbursements of counsel) under clauses (ix), (x) and (xi). It is understood, however, that, except as expressly provided in this Section 7, Sections 9, 10 and 14 hereof, the Underwriters will pay all of their own costs and expenses, including the fees of their counsel, transfer taxes on resale of any of the Securities by them, and any advertising expenses connected with any offers they may make.

8. The obligations of the Underwriters hereunder, as to the Securities to be delivered at the applicable Time of Delivery, shall be subject, in their discretion, to the condition that all representations and warranties and other statements of the Company herein are, at and as of such Time of Delivery, true and correct, the condition that the Company shall have performed all of its obligations hereunder theretofore to be performed, and the following additional conditions:

(a) The Prospectus shall have been filed with the Commission pursuant to Rule 424(b) under the Act within the applicable time period prescribed for such filing by the Rules and Regulations and in accordance with Section 5(a) hereof; if the Company has elected to rely upon Rule 462(b) under the Act, the Rule 462(b) Registration Statement shall have become effective by 10:00 p.m., Washington, D.C. time, on the date of this Agreement; no stop order suspending the effectiveness of the Registration Statement or any part thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; no stop order suspending or preventing the use of the Prospectus shall have been initiated or threatened by the Commission; and all requests for additional information on the part of the Commission shall have been complied with to your reasonable satisfaction;

(b) Latham & Watkins LLP, counsel for the Underwriters, shall have furnished to you such written opinion and negative assurance letter, dated the First Time of Delivery or the date of the applicable Subsequent Time of Delivery, as the case may be, in form and substance reasonably satisfactory to you, with respect to the matters you may reasonably request, and such counsel shall have received such papers and information as they may reasonably request to enable them to pass upon such matters;

(c) Cravath, Swaine & Moore LLP, counsel for the Company, shall have furnished to you their written opinion and negative assurance letter, dated the First Time of Delivery or the date of the applicable Subsequent Time of Delivery, as the case may be, in form and substance reasonably satisfactory to you;

(d) On the date of this Agreement and at each Time of Delivery, Grant Thornton LLP shall have furnished to you a comfort letter, dated the respective dates of delivery thereof, in form and substance reasonably satisfactory to you, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus; provided, that the letter delivered on the First Time of Delivery or each Subsequent Time of Delivery, as the case may be, shall use a “cut-off” date no more than three business days prior to such First Time of Delivery or such Subsequent Time of Delivery, as the case may be;

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(e) (i) Neither the Company nor its subsidiary shall have sustained since the date of the latest financial statements included in the Pricing Disclosure Package any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Disclosure Package, and (ii) since the respective dates as of which information is given in the Pricing Disclosure Package there shall not have been any change in the capital stock or long-term debt of the Company or its subsidiary or any change, or any development involving a prospective change, in or affecting the properties, business, management, prospects, operations, earnings, assets, liabilities or condition (financial or otherwise) of the Company and its subsidiary, otherwise than as set forth or contemplated in the Pricing Disclosure Package, the effect of which, in any such case described in clause (i) or (ii), is in your judgment so material and adverse as to make it impracticable or inadvisable to proceed with the public offering or the delivery of the Securities being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(f) The Representatives shall have received on and as of the First Time of Delivery or each Subsequent Time of Delivery, as the case may be, satisfactory evidence of the good standing (or its jurisdictional equivalent) of the Company and its subsidiary in their respective jurisdictions of organization and their good standing in such other jurisdictions as the Representatives may reasonably request, in each case, in writing or any standard form of telecommunication from the appropriate governmental authorities of such jurisdiction;

(g) On or after the Applicable Time there shall not have occurred any of the following: (i) a suspension or material limitation in trading in securities generally on the New York Stock Exchange or on the Nasdaq Global Market; (ii) a suspension or material limitation in trading in the Company’s securities on the Nasdaq Global Market; (iii) a general moratorium on commercial banking activities declared by either Federal or New York authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (i) through (v) in your judgment is material and adverse and makes it impracticable or inadvisable to proceed with the public offering or the delivery of the Securities being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(h) The Securities to be delivered at the First Time of Delivery or each Subsequent Time of Delivery, as the case may be, shall have been approved for listing on the Nasdaq Global Market, subject to official notice of issuance;

(i) The Company shall have obtained and delivered to the Underwriters executed copies of a lock-up letter, from the persons and entities listed on Schedule III hereto, substantially to the effect set forth in Annex I hereof;

(j) The Company shall have complied with the provisions of Section 5(c) hereof with respect to the furnishing of prospectuses on the New York Business Day next succeeding the date of this Agreement;

(k) The Company shall have furnished or caused to be furnished to you at such Time of Delivery a certificate of the Chief Executive Officer and the Chief Financial Officer of the Company, in their capacities as such and not in their personal capacities, reasonably satisfactory to you as to (i) the accuracy of the representations and warranties of the Company herein at and as of such time, (ii) the

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performance by the Company of all of its obligations hereunder to be performed at or prior to such time, (iii) the matters set forth in subsections (a), (e) and (g) of this Section 8 and (iv) such other matters as you may reasonably request; and

(l) The Company will furnish the Representatives with any additional opinions, certificates, letters and documents as the Representatives reasonably request and conformed copies of documents delivered pursuant to this Section 8. The Representatives may in their sole discretion waive on behalf of the Underwriters compliance with any one or more conditions to the obligations of the Underwriters hereunder.

9. (a) The Company will indemnify and hold harmless each Underwriter, its affiliates, directors and officers and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Act or Section 20 of the Exchange Act, against any losses, claims, damages or liabilities (collectively, “Losses”), joint or several, to which such Underwriter may become subject, under the Act or otherwise, insofar as such Losses (i) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus, or any amendment or supplement thereto, or any road show as defined in Rule 433(h) under the Act (a “road show”), or any Written Testing-the-Waters Communication, or (ii) arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, and will reimburse each Underwriter for any documented out-of-pocket legal or other expenses reasonably incurred by such Underwriter in connection with investigating or defending any such action or claim as such expenses are incurred (collectively, “Expenses”); provided, however, that the Company shall not have any obligation to indemnify and hold harmless, or to reimburse, hereunder in respect of any Losses or Expenses to the extent that any such Losses or Expenses arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in the Registration Statement, any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus, or any amendment or supplement thereto or any Written Testing-the-Waters Communication in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information provided by any Underwriter through the Representatives is that identified as such in Section 9(b).

(b) Each Underwriter will indemnify and hold harmless the Company, its affiliates, directors and officers and each person, if any, who controls the Company within the meaning of Section 15 of the Act or Section 20 of the Exchange Act, against any Losses to which the Company may become subject, under the Act or otherwise, insofar as such Losses (or actions in respect thereof) (i) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus, or any amendment or supplement thereto, or any road show or any Written Testing-the-Waters Communication or (ii) arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in the Registration Statement, any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus or any such amendment or supplement thereto, or any Written Testing-the-Waters Communication, in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information provided by any Underwriter through the Representatives is the information contained in the [•] paragraphs under the caption “Underwriting” in the Preliminary Prospectus and the

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Prospectus; and will reimburse the Company for any documented legal or other expenses reasonably incurred by the Company in connection with investigating or defending any such action or claim as such expenses are incurred.

(c) Promptly after receipt by an indemnified party under subsection (a) or (b) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing with reasonable promptness of the commencement thereof; but the omission so to notify the indemnifying party shall not relieve it from any liability which it may have to any indemnified party under such subsection, except to the extent that the indemnifying party has been materially prejudiced by such failure. In case any such action shall be brought against any indemnified party and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel reasonably satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and, after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation; provided, however, that if, in the sole judgment of the Representative, it is advisable for the Underwriters to be represented as a group by separate counsel, the Representative shall have the right to employ a single counsel (in addition to a single local counsel) to represent the Representative and all Underwriters that may be subject to liability arising from any claim in respect of which indemnity may be sought by the Underwriters under subsection (a) above in which event the reasonable and documented fees and expenses of such separate counsel shall be borne by the indemnifying party or parties and reimbursed to the Underwriters as incurred. No indemnifying party shall, without the written consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the indemnified party from all liability arising out of such action or claim and (ii) does not include a statement as to or an admission of fault, culpability or a failure to act, by or on behalf of any indemnified party. Notwithstanding the foregoing, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel pursuant to this Section 9(c), such indemnifying party agrees that it shall be liable for any settlement effected without its written consent if (i) such settlement is entered into more than 45 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed such indemnified party in accordance with such request prior to the date of such settlement.

(d) If the indemnification provided for in this Section 9 is unavailable to or insufficient to hold harmless an indemnified party under subsection (a) or (b) above in respect of any Losses referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such Losses in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Securities. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the indemnified party failed to give the notice required under subsection (c) above, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative

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benefits but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such Losses, as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the Prospectus. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or the Underwriters on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this subsection (d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this subsection (d). The amount paid or payable by an indemnified party as a result of the Losses referred to above in this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total underwriting discounts and commissions received by such Underwriter with respect to the offering of the Securities exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this subsection (d) to contribute are several in proportion to their respective underwriting obligations and not joint.

(e) The obligations of the Company under this Section 9 shall be in addition to any liability which the Company may otherwise have and shall extend, upon the same terms and conditions, to each person, if any, who controls any Underwriter within the meaning of the Act and each affiliate of any Underwriter within the meaning of Rule 405 under the Act, including, without limitation, the officers, directors, partners and members of each such Underwriter and its broker-dealer affiliates; and the obligations of the Underwriters under this Section 9 shall be in addition to any liability which the respective Underwriters may otherwise have and shall extend, upon the same terms and conditions, to each officer and director of the Company and to each person, if any, who controls the Company within the meaning of the Act.

10. (a) The Company agrees to indemnify and hold harmless William Blair, each person, if any, who controls William Blair within the meaning of Section 15 of the Act or Section 20 of the Exchange Act, and each affiliate of William Blair within the meaning of Rule 405 under the Act (collectively, the “DSP Indemnified Parties”) from and against any Losses, joint or several, to which William Blair may become subject, under the Act or otherwise, insofar as such Losses (i) arise out of, or are based upon, any untrue statement or alleged untrue statement of a material fact contained in any material prepared by or with the consent of the Company for distribution to Participants in connection with the Directed Share Program or arise out of, or are based upon, any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading; (ii) arise out of, or are based upon, the failure of any Participant to pay for and accept delivery of Directed Shares that the Participant agreed to purchase; or (iii) are related to, arise out of, or are in connection with the Directed Share Program, other than Losses (or Expenses relating thereto) that are finally judicially determined to have resulted from the bad faith or gross negligence

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of the DSP Indemnified Parties; and will reimburse each DSP Indemnified Party for any documented out-of-pocket legal or other expenses reasonably incurred by such DSP Indemnified Party in connection with investigating or defending any such action or claim as such expenses are incurred.

(b) Promptly after receipt by a DSP Indemnified Party of notice of the commencement of any action in respect of which indemnity may be sought pursuant to subsection (a) above, such DSP Indemnified Party shall, if a claim in respect thereof is to be made against the Company under such subsection, notify the Company in writing with reasonable promptness of the commencement thereof; but the omission so to notify the Company shall not relieve it from any liability which it may have to any DSP Indemnified Party under such subsection, except to the extent that the Company has been materially prejudiced by such failure. In case any such action shall be brought against any DSP Indemnified Party and it shall notify the Company of the commencement thereof, the Company shall be entitled to participate therein and, to the extent that it shall wish, to assume the defense thereof, with counsel reasonably satisfactory to such DSP Indemnified Party (who shall not, except with the consent of the DSP Indemnified Party, be counsel to the Company), and, after notice from the Company to such DSP Indemnified Party of its election so to assume the defense thereof, the Company shall not be liable to such DSP Indemnified Party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by such DSP Indemnified Party, in connection with the defense thereof other than reasonable costs of investigation; provided, however, that if, in the sole judgment of William Blair, it is advisable for William Blair to be represented by separate counsel, William Blair shall have the right to employ a single counsel (in addition to a single local counsel) to represent William Blair and all DSP Indemnified Parties that may be subject to liability arising from any claim in respect of which indemnity may be sought under subsection (a) above in which event the reasonable and documented fees and expenses of such separate counsel shall be borne by the Company and reimbursed to the DSP Indemnified Parties as incurred. No party shall, without the written consent of the other party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the DSP Indemnified Party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the DSP Indemnified Parties from all liability arising out of such action or claim and (ii) does not include a statement as to or an admission of fault, culpability or a failure to act, by or on behalf of any DSP Indemnified Party. Notwithstanding the foregoing, if at any time a DSP Indemnified Party shall have requested the Company to reimburse such DSP Indemnified Party for fees and expenses of counsel pursuant to this Section 10(b), the Company agrees that it shall be liable for any settlement effected without its written consent if (i) such settlement is entered into more than 45 days after receipt by the Company of the aforesaid request and (ii) the Company shall not have reimbursed such DSP Indemnified Party in accordance with such request prior to the date of such settlement.

(c) To the extent the indemnification provided for in subsection (a) above is unavailable to a DSP Indemnified Party or insufficient in respect of any Losses referred to therein, then the Company, in lieu of indemnifying the DSP Indemnified Party thereunder, shall contribute to the amount paid or payable by the DSP Indemnified Party as a result of such Losses (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the DSP Indemnified Parties on the other hand from the offering of the Directed Shares or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company on the one hand and of the DSP Indemnified Parties on the other hand in connection with any statements or omissions that resulted in such Losses, as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the DSP

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Indemnified Parties on the other hand in connection with the offering of the Directed Shares shall be deemed to be in the same respective proportions as the net proceeds from the offering of the Directed Shares (before deducting expenses) received by the Company and the total underwriting discounts and commissions received by the DSP Indemnified Parties for the Directed Shares, bear to the aggregate purchase price of the Directed Shares. The relative fault of the Company on the one hand and the DSP Indemnified Parties on the other hand shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or by the DSP Indemnified Parties on the other hand and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

(d) The Company and the DSP Indemnified Parties agree that it would not be just or equitable if contribution pursuant to subsection (c) above were determined by pro rata allocation (even if the DSP Indemnified Parties were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in subsection (c) above. The amount paid or payable by the DSP Indemnified Parties as a result of the Losses referred to in subsection (c) above shall be deemed to include any legal or other expenses reasonably incurred by the DSP Indemnified Parties in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this subsection (d), no DSP Indemnified Party shall be required to contribute any amount in excess of the amount by which the total price at which the Directed Shares distributed to the public were offered to the public exceeds the amount of any damages that such DSP Indemnified Party has otherwise been required to pay. The remedies provided for in this Section 10 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any DSP Indemnified Party at law or in equity.

(e) The indemnity and contribution provisions contained in this Section 10 shall remain operative and in full force and effect regardless of (i) any termination of this Agreement, (ii) any investigation made by or on behalf of any DSP Indemnified Party or the Company, its officers or directors or any person controlling the Company and (iii) acceptance of and payment for any of the Directed Shares.

11. This Agreement may be terminated by written notice given by the Representatives to the Company, if after the execution and delivery of this Agreement and on or prior to the First Time of Delivery or, in the case of any Option Securities, prior to the Subsequent Time of Delivery for such Option Securities (i) a suspension or material limitation in trading in securities generally on the New York Stock Exchange or on the Nasdaq Global Market; (ii) a general moratorium on commercial banking activities declared by either Federal or New York authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iii) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (iv) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (i) through (iv) in the judgment of the Representatives, is material and adverse and makes it impracticable or inadvisable to proceed with the public offering or the delivery of the Securities on the First Time of Delivery or such Subsequent Time of Delivery, as the case may be, on the terms and in the manner contemplated by the Prospectus.

12. (a) If any Underwriter shall default in its obligation to purchase the Securities which it has agreed to purchase hereunder at a Time of Delivery, you may in your discretion arrange for you or another party or other parties to purchase such Securities on the terms contained herein. If within thirty-six hours after such default by any Underwriter you do not arrange for the purchase of such

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Securities, then the Company shall be entitled to a further period of thirty-six hours within which to procure another party or other parties satisfactory to you to purchase such Securities on such terms. In the event that, within the respective prescribed periods, you notify the Company that you have so arranged for the purchase of such Securities, or the Company notifies you that it has so arranged for the purchase of such Securities, you or the Company shall have the right to postpone such Time of Delivery for a period of not more than seven days, in order to effect whatever changes may thereby be made necessary in the Registration Statement or the Prospectus, or in any other documents or arrangements, and the Company agrees to file promptly any amendments or supplements to the Registration Statement or the Prospectus which in your opinion may thereby be made necessary. The term “Underwriter” as used in this Agreement shall include any person substituted under this Section 12 with like effect as if such person had originally been a party to this Agreement with respect to such Securities.

(b) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters by you and the Company as provided in subsection (a) above, the aggregate number of such Securities which remains unpurchased does not exceed one eleventh of the aggregate number of all the Securities to be purchased at such Time of Delivery, then the Company shall have the right to require each non-defaulting Underwriter to purchase the number of shares which such Underwriter agreed to purchase hereunder at such Time of Delivery and, in addition, to require each non-defaulting Underwriter to purchase its pro rata share (based on the number of Securities which such Underwriter agreed to purchase hereunder) of the Securities of such defaulting Underwriter or Underwriters for which such arrangements have not been made; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

(c) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters by you and the Company as provided in subsection (a) above, the aggregate number of such Securities which remains unpurchased exceeds one eleventh of the aggregate number of all the Securities to be purchased at such Time of Delivery, or if the Company shall not exercise the right described in subsection (b) above to require non-defaulting Underwriters to purchase Securities of a defaulting Underwriter or Underwriters, then this Agreement (or, with respect to each Subsequent Time of Delivery, the obligation of the Underwriters to purchase and of the Company to sell the Optional Securities) shall thereupon terminate, without liability on the part of any non-defaulting Underwriter or the Company, except for the expenses to be borne by the Company and the Underwriters as provided in Section 7 hereof and the indemnity and contribution agreements in Sections 9 and 10 hereof; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

13. The respective indemnities, agreements, representations, warranties and other statements of the Company and the several Underwriters, as set forth in this Agreement or made by or on behalf of them, respectively, pursuant to this Agreement, shall remain in full force and effect, regardless of any investigation (or any statement as to the results thereof) made by or on behalf of any Underwriter or any controlling person of any Underwriter, or the Company, or any officer or director or controlling person of the Company, and shall survive delivery of and payment for the Securities.

14. If this Agreement shall be terminated pursuant to Section 12 hereof, the Company shall not then be under any liability to any defaulting Underwriter; but, if for any other reason (except for a reason specified in Section 11), any Securities are not delivered by or on behalf of the Company as provided herein, the Company will reimburse the Underwriters through you for all documented out-of-pocket expenses in an aggregate amount not to exceed $200,000, including fees and disbursements of counsel for the Underwriters, reasonably incurred by the Underwriters in making

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preparations for the purchase, sale and delivery of the Securities not so delivered, but the Company shall then be under no further liability to any Underwriter except as provided in Sections 9 and 10 hereof.

15. In all dealings hereunder, you shall act on behalf of each of the Underwriters, and the parties hereto shall be entitled to act and rely upon any statement, request, notice or agreement on behalf of any Underwriter made or given by you.

All statements, requests, notices and agreements hereunder shall be in writing, and if to the Underwriters shall be delivered or sent by mail, facsimile or email transmission to William Blair & Company, L.L.C., 150 North Riverside Plaza, Chicago, IL 60606, Attention: General Counsel, Facsimile: (312) 551-4646, email: CHenderson@williamblair.com and Stifel, Nicolaus & Company, Incorporated, 787 Seventh Avenue, 11th Floor, New York, New York 10019; and if to the Company shall be delivered or sent by mail or facsimile transmission to the address of the Company set forth on the cover of the Registration Statement, Attention: Jon Gordon, General Counsel, E-mail: jon.gordon@deepfission.com, (with copies to those parties specified thereon). Any such statements, requests, notices or agreements shall take effect upon receipt thereof.

In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients.

16. This Agreement shall be binding upon, and inure solely to the benefit of, the Underwriters, the Company and, to the extent provided in Sections 9, 10 and 13 hereof, the officers and directors of the Company and each person who controls the Company or any Underwriter, and their respective heirs, executors, administrators, successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. No purchaser of any of the Securities from any Underwriter shall be deemed a successor or assign by reason merely of such purchase.

17. As used herein, the term “business day” shall mean any day when the Commission’s office in Washington, D.C. is open for business and “New York Business Day” shall mean each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in New York City are generally authorized or obligated by law or executive order to close.

18. The Company acknowledges and agrees that (i) the purchase and sale of the Securities pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other, (ii) in connection therewith and with the process leading to such transaction each Underwriter is acting solely as a principal and not the agent or fiduciary of the Company, (iii) no Underwriter has assumed an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) or any other obligation to the Company except the obligations expressly set forth in this Agreement and (iv) the Company has consulted its own legal and financial advisors to the extent it deemed appropriate. The Company agrees that it will not claim that the Underwriters, or any of them, has rendered advisory services of any nature or respect, or owes a fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

-28-


19. The Company acknowledges that the Underwriters’ research analysts and research departments are required to be independent from their respective investment banking divisions and are subject to certain regulations and internal policies, and that such Underwriters’ research analysts may hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering that differ from the views of their respective investment banking divisions. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the Underwriters with respect to any conflict of interest that may arise from the fact that the views expressed by their independent research analysts and research departments may be different from or inconsistent with the views or advice communicated to the Company by such Underwriters’ investment banking divisions. The Company acknowledges that each of the Underwriters is a full service securities firm and as such from time to time, subject to applicable securities laws, may effect transactions for its own account or the account of its customers and hold long or short positions in debt or equity securities of the companies that may be the subject of the transactions contemplated by this Agreement.

20. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriters, or any of them, with respect to the subject matter hereof.

21. THIS AGREEMENT AND ANY MATTERS RELATED TO THIS TRANSACTION SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICT OF LAWS THAT WOULD RESULT IN THE APPLICATION OF ANY LAW OTHER THAN THE LAWS OF THE STATE OF NEW YORK. The Company and each of the Underwriters agree that any suit or proceeding arising in respect of this Agreement or any matters related to this transaction will be tried exclusively in the U.S. District Court for the Southern District of New York or, if that court does not have subject matter jurisdiction, in any state court located in The City and County of New York and the Company and each of the Underwriters agree to submit to the jurisdiction of, and to venue in, such courts.

22. The Company and each of the Underwriters hereby irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

23. (i) In the event that any Underwriter that is a Covered Entity becomes subject to a proceeding under a U.S. Special Resolution Regime, the transfer from such Underwriter of this Agreement, and any interest and obligation in or under this Agreement, will be effective to the same extent as the transfer would be effective under the U.S. Special Resolution Regime if this Agreement, and any such interest and obligation, were governed by the laws of the United States or a state of the United States.

(ii) In the event that any Underwriter that is a Covered Entity or a BHC Act Affiliate of such Underwriter becomes subject to a proceeding under a U.S. Special Resolution Regime, Default Rights under this Agreement that may be exercised against such Underwriter are permitted to be exercised to no greater extent than such Default Rights could be exercised under the U.S. Special Resolution Regime if this Agreement were governed by the laws of the United States or a state of the United States.

As used in this Section 23:

BHC Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted in accordance with, 12 U.S.C. § 1841(k).

-29-


Covered Entity” means any of the following:

(i) a “covered entity” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b);

(ii) a “covered bank” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 47.3(b); or

(iii) a “covered FSI” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 382.2(b).

Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable.

U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

24. This Agreement may be executed by any one or more of the parties hereto in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same instrument. Counterparts may be delivered via facsimile, electronic mail (including any electronic signature covered by the U.S. federal ESIGN Act of 2000, Uniform Electronic Transactions Act, the Electronic Signatures and Records Act or other applicable law, e.g., www.docusign.com) or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes.

25. Notwithstanding anything herein to the contrary, the Company is authorized to disclose to any persons the U.S. federal and state income tax treatment and tax structure of the potential transaction and all materials of any kind (including tax opinions and other tax analyses) provided to the Company relating to that treatment and structure, without the Underwriters imposing any limitation of any kind. However, any information relating to the tax treatment and tax structure shall remain confidential (and the foregoing sentence shall not apply) to the extent necessary to enable any person to comply with securities laws. For this purpose, “tax structure” is limited to any facts that may be relevant to that treatment.

26. If any term or other provision of this Agreement shall be held invalid, illegal or unenforceable, the validity, legality or enforceability of the other provisions of this Agreement shall not be affected thereby, and there shall be deemed substituted for the provision at issue a valid, legal and enforceable provision as similar as possible to the provision at issue.

27. Except as otherwise expressly provided herein, the provisions of this Agreement may be amended or waived at any time only by the written agreement of the parties hereto. Any waiver, permit, consent or approval of any kind or character on the part of any such holders of any provision or condition of this Agreement must be made in writing and shall be effective only to the extent specifically set forth in writing. The failure of any party hereto to enforce at any time any provision of this Agreement shall not be construed to be a waiver of such provision, nor in any way to affect the validity of this Agreement or any part hereof or the right of any party thereafter to enforce each and every such provision. No waiver of any breach of this Agreement shall be held to constitute a waiver of any other or subsequent breach.

[Signature page follows]

-30-


If the foregoing is in accordance with your understanding, please sign and return to us, and upon the acceptance hereof by you, on behalf of each of the Underwriters, this Agreement and such acceptance hereof shall constitute a binding agreement between each of the Underwriters and the Company.

Very truly yours,

DEEP FISSION, INC.

By:

Name:

Title:

Accepted as of the date hereof:

WILLIAM BLAIR & COMPANY, L.L.C.

STIFEL, NICOLAUS & COMPANY, INCORPORATED

Acting severally on behalf of themselves and

the several Underwriters named in Schedule I

hereto

WILLIAM BLAIR & COMPANY, L.L.C.

Name:

Title:

STIFEL, NICOLAUS & COMPANY, INCORPORATED

Name:

Title:

-31-


SCHEDULE I

Underwriter

  ​ ​ ​

Total
Number of
Firm
Securities
to be
Purchased

  ​ ​ ​

Number of
Optional
Securities to
be Purchased

if Maximum

Option

Exercised

William Blair & Company, L.L.C.

[●]

[●]

Stifel, Nicolaus & Company, Incorporated

[●]

[●]

Canaccord Genuity LLC

[●]

[●]

Seaport Global Securities LLC

[●]

[●]

The Benchmark Company, LLC

[●]

[●]

[●]

Total

[●]

[●]

-32-


SCHEDULE II

Information other than the Preliminary Prospectus that comprise the Pricing Disclosure Package:

The public offering price per share for the Securities is $[●].

The number of Firm Securities purchased by the Underwriters is [●].

The number of Optional Securities that may be purchased at the option of the Underwriters is [●].

-33-


SCHEDULE III

1.

Jonathon Angell

2.

Michael Brasel

3.

Thomas S. Glanville

4.

Blake Janover

5.

Elizabeth Muller (including Muller Family Trust)

6.

Richard Muller

7.

Leslie Goldman Tepper (including Bella AJT Holdings)

8.

Mark (William) Schmitz

9.

Jon Gordon

10.

Mark Peres

11.

Stacy Tarver Patterson

-34-


Schedule IV

Written Testing-the-Waters Communications

Testing the Waters Presentation dated April 2026

[●]


Annex I

[Form of Lock-Up Letter]


[●], 2026

WILLIAM BLAIR & COMPANY, L.L.C.

STIFEL, NICOLAUS & COMPANY, INCORPORATED

As Representatives of the several Underwriters listed in Schedule I to the Underwriting

Agreement referred to below

c/o William Blair & Company, L.L.C.

150 North Riverside Plaza

Chicago, Illinois 60606

c/o Stifel, Nicolaus & Company, Incorporated

787 Seventh Avenue, 11th Floor

New York, New York 10019

Re:Deep Fission, Inc. — Public Offering

Ladies and Gentlemen:

The undersigned understands that William Blair & Company, L.L.C. (“William Blair”) and Stifel, Nicolaus & Company, Incorporated, as Representatives of the several Underwriters, propose to enter into an underwriting agreement (the “Underwriting Agreement”) with Deep Fission, Inc., a Delaware corporation (the “Company”), providing for the public offering (the “Public Offering”) by the several Underwriters named in Schedule I to the Underwriting Agreement (the “Underwriters”), of shares (the “Securities”) of common stock, par value $0.0001 per share, of the Company (the “Common Stock”). Capitalized terms used herein and not otherwise defined shall have the meanings set forth in the Underwriting Agreement.

In consideration of the Underwriters’ agreement to purchase and make the Public Offering of the Securities, and for other good and valuable consideration receipt of which is hereby acknowledged, the undersigned hereby agrees that, without the prior written consent of William Blair on behalf of the Underwriters, the undersigned will not, and will not cause any direct or indirect affiliate to, during the period beginning on the date of this letter agreement (this “Letter Agreement”) and ending at the close of business on the date that is 180 days after the date of the final prospectus relating to the Public Offering (the “Prospectus”) (such period, the “Restricted Period”), (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock (including without limitation, Common Stock or such other securities which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the Commission and securities which may be issued upon exercise of a stock option or warrant) (such shares of Common Stock, options, rights, warrants or other securities, collectively, “Lock-Up Securities”), (2) enter into any hedging, swap, forward or other agreement or transaction (including, without limitation, any short sale or the purchase or sale of, or entry into, any put or call option, or combination thereof, forward, swap or any other derivative transaction or instrument, however described or defined) that transfers, in whole or in part, any of the economic


consequences of ownership of the Lock-Up Securities, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Lock-Up Securities, in cash or otherwise, (3) make any demand for or exercise any right with respect to the registration (including, but not limited to the filing or confidential submission of a registration statement in connection therewith) of any Lock-Up Securities, or (4) publicly disclose the intention to do any of the foregoing (each of the foregoing (1) through (4), a “Transfer”). The undersigned represents and warrants that it is not, and has not caused or directed any of its affiliates to be or become, currently a party to any agreement or arrangement that provides for, is designed to or which reasonably could be expected to lead to or result in any Transfer during the Restricted Period in violation of this Letter Agreement.

Notwithstanding the foregoing, the undersigned may:

(a)

transfer the undersigned’s Lock-Up Securities:

(i) as a bona fide gift or gifts or charitable contributions, or for bona fide estate planning purposes,

(ii) upon death or by will, other testamentary document or intestacy,

(iii) to any immediate family of the undersigned or to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, or if the undersigned is a trust, to a trustor or beneficiary of the trust or to the estate of a beneficiary of such trust (for purposes of this Letter Agreement, “immediate family” shall mean any relationship by blood, current or former marriage, current or former domestic partnership or adoption, or any cousin not more remote than first cousin),

(iv) to a corporation, partnership, limited liability company or other entity of which the undersigned and the immediate family of the undersigned are the legal and beneficial owner of all of the outstanding equity securities or similar interests,

(v) to a nominee or custodian of a person or entity to whom a disposition or transfer would be permissible under clauses (i) through (iv) above,

(vi) if the undersigned is a corporation, partnership, limited liability company, trust or other business entity, (A) to another corporation, partnership, limited liability company, trust or other business entity that is an affiliate (as defined in Rule 405 promulgated under the Securities Act of 1933, as amended) of the undersigned, or to any investment fund or other entity controlling, controlled by, managing or managed by or under common control with the undersigned or affiliates of the undersigned (including, for the avoidance of doubt, where the undersigned is a partnership, to its general partner or a successor partnership or fund, or any other funds managed by such partnership), (B) as part of a Transfer without consideration to shareholders, current or former partners (general or limited), current or former members, beneficiaries or other equity holders, or to the estates of any such shareholders, partners, beneficiaries or other equity holders of the undersigned, (C) to any wholly owned subsidiary of the undersigned or (D) if a transferee referred to under clauses (vi)(A) to (C) above is not a natural person, any director or indirect partner, member, shareholder or equityholder of such transferee until the Lock-Up Securities come to be held by a natural person,


(vii) by operation of law, such as pursuant to a qualified domestic order, divorce settlement, divorce decree or separation agreement, or pursuant to the order of a court or regulatory agency,

(viii) to the Company from an employee of the Company upon death, disability or termination of employment, in each case, of such employee,

(ix) as part of a sale of the undersigned’s Lock-Up Securities acquired in open market transactions after the closing date for the Public Offering,

(x) to the Company in connection with the vesting, settlement, or exercise of restricted stock awards, restricted stock units, options, warrants or other rights to purchase shares of Common Stock (including, in each case, by way of “net” or “cashless” exercise), including for the payment of exercise price and tax and remittance payments due as a result of the vesting, settlement, or exercise of such restricted stock awards, restricted stock units, options, warrants or rights; provided that any such shares of Common Stock received upon such vesting, settlement or exercise shall be subject to the terms of this Letter Agreement, and provided further that any such restricted stock awards, restricted stock units, options, warrants or rights were granted prior to the date hereof or are held by the undersigned pursuant to an agreement or equity awards granted under a stock incentive plan or other equity award plan, each such agreement or plan which is described in the Registration Statement, the Pricing Disclosure Package and the Prospectus,

(xi) pursuant to a bona fide third-party tender offer, merger, consolidation or other similar transaction that is approved by the Board of Directors of the Company and made to all holders of the Company’s capital stock involving a Change of Control (as defined below) of the Company (for purposes hereof, “Change of Control” shall mean the transfer (whether by tender offer, merger, consolidation or other similar transaction), in one transaction or a series of related transactions, to a person or group of affiliated persons, of shares of capital stock if, after such transfer, the stockholders of the Company immediately prior to such transfer do not hold at least a majority of the outstanding voting securities of the Company (or the surviving entity)); provided that in the event that such tender offer, merger, consolidation or other similar transaction is not completed, the undersigned’s Lock-Up Securities shall remain subject to the provisions of this Letter Agreement, or

(xii) Transfer Lock-Up Securities pursuant to arrangements under which the Company has the option to repurchase such Lock-Up Securities,

provided that (A) in the case of any transfer or distribution pursuant to clause (a)(i), (ii), (iii), (iv), (v), (vi) and (vii), such transfer shall not involve a disposition for value, except in the case of clause (a)(vii), and each donee, devisee, transferee or distributee shall execute and deliver to the Representatives a lock-up letter in the form of this Letter Agreement, (B) in the case of any transfer or distribution pursuant to clause (a)(i), (ii), (iii), (iv), (v), (vi), (vii), (viii), (ix) and (x), it shall be a condition to such transfer that no public filing, report or announcement shall be voluntarily made and if any filing under Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or other public filing, report or announcement reporting a reduction in beneficial ownership of shares of Common Stock in connection with such transfer or distribution shall be legally required during the Restricted Period, such filing, report or announcement shall clearly indicate in the footnotes thereto the nature and conditions of such transfer;


(b)exercise outstanding options, settle restricted stock units or other equity awards or exercise warrants pursuant to agreements or equity awards granted under a stock incentive plan or other equity award plan described in the Registration Statement, the Pricing Disclosure Package and the Prospectus; provided that any Lock-Up Securities received upon such exercise, vesting or settlement shall be subject to the terms of this Letter Agreement;

(c)convert outstanding preferred stock, warrants to acquire preferred stock or convertible securities into shares of Common Stock or warrants to acquire shares of Common Stock; provided that any such shares of Common Stock or warrants received upon such conversion shall be subject to the terms of this Letter Agreement; and

(d)establish or amend trading plans pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Lock-Up Securities; provided that (i) such plans do not provide for the transfer of Lock-Up Securities during the Restricted Period and (ii) to the extent a public announcement or filing under the Exchange Act, if any, is required of the undersigned or the Company regarding the establishment or amendment of such plan, such announcement or filing shall include a statement to the effect that no transfer of Lock-Up Securities may be made under such plan during the Restricted Period.

If the undersigned is an officer or director of the Company, the undersigned further agrees that the foregoing provisions shall be equally applicable to any Company-directed or other Securities the undersigned may purchase in the Public Offering.

If the undersigned is an officer or director of the Company, (i) William Blair, on behalf of the Underwriters, agrees that, at least three business days before the effective date of any release or waiver of the foregoing restrictions in connection with a transfer of shares of Lock-Up Securities, William Blair, on behalf of the Underwriters, will notify the Company of the impending release or waiver, and (ii) the Company has agreed in the Underwriting Agreement to announce the impending release or waiver through a major news service at least two business days before the effective date of the release or waiver. Any release or waiver granted by William Blair on behalf of the Underwriters hereunder to any such officer or director shall only be effective two business days after the publication date of such announcement. The provisions of this paragraph will not apply if (a) the release or waiver is effected solely to permit a transfer not for consideration or that is to an immediate family member as defined in FINRA Rule 5130(i)(5) and (b) the transferee has agreed in writing to be bound by the same terms described in this Letter Agreement to the extent and for the duration that such terms remain in effect at the time of the transfer.

In furtherance of the foregoing, the Company, and any duly appointed transfer agent for the registration or transfer of the securities described herein, are hereby authorized to decline to make any transfer of securities if such transfer would constitute a violation or breach of this Letter Agreement.

The undersigned understands that the Company and the Underwriters are entering into the Underwriting Agreement and proceeding with the Public Offering in reliance upon this Letter Agreement. The undersigned further understands that this Letter Agreement is irrevocable and shall be binding upon the undersigned’s heirs, legal representatives, successors and assigns.


The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Letter Agreement. All authority herein conferred or agreed to be conferred and any obligations of the undersigned shall be binding upon the successors, assigns, heirs or personal representatives of the undersigned.

The undersigned acknowledges and agrees that the Underwriters have not provided any recommendation or investment advice nor have the Underwriters solicited any action from the undersigned with respect to the Public Offering of the Securities and the undersigned has consulted its own legal, accounting, financial, regulatory and tax advisors to the extent deemed appropriate. The undersigned further acknowledges and agrees that, although the Representatives may be required or choose to provide certain Regulation Best Interest and Form CRS disclosures to the undersigned in connection with the Public Offering, the Representatives and the other Underwriters are not making a recommendation to the undersigned to enter into this Letter Agreement, participate in the Public Offering, or sell any Securities at the price determined in the Public Offering, and nothing set forth in such disclosures is intended to suggest that the Representatives or any Underwriter is making such a recommendation.

The undersigned understands that, upon the earliest date to occur, if any, (i) the date that the Company advises the Representatives, in writing, prior to the execution of the Underwriting Agreement, that it has determined not to proceed with the Public Offering, (ii) the date that the Company withdraws the registration statement related to the Public Offering before the execution of the Underwriting Agreement, (iii) if the Underwriting Agreement is executed but terminated (other than the provisions thereof which survive termination) prior to payment for and delivery of the Common Stock to be sold thereunder, the date that the Underwriting Agreement is terminated or (iv) if the Underwriting Agreement has not yet become effective, [•], 2026, this Letter Agreement shall automatically terminate, and the undersigned shall be released from all obligations under this Letter Agreement.

This Letter Agreement and any claim, controversy or dispute arising under or related to this Letter Agreement shall be governed by and construed in accordance with the laws of the State of New York.

Signatures to this Letter Agreement may be delivered via facsimile, electronic mail (including any electronic signature covered by the U.S. federal ESIGN Act of 2000, Uniform Electronic Transactions Act, the Electronic Signatures and Records Act or other applicable law, e.g., www.docusign.com) or other transmission method and any signature so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes.


Very truly yours,

[NAME OF STOCKHOLDER]

By:

Name:

Title:


Annex II

Form of Waiver of Lock-up

Deep Fission, Inc.

Public Offering of Common Stock

[Name and Address of
Officer or Director
Requesting Waiver]

Dear Mr./Ms. [Name]:

This letter is being delivered to you in connection with the offering by Deep Fission, Inc. (the “Company”) of [ ● ] shares of common stock, $0.0001 par value (the “Common Stock”), of the Company and the lock-up letter dated [ ● ], 2026 (the “Lock-up Letter”), executed by you in connection with such offering, and your request for a [release] [waiver] dated [ ● ], 2026, with respect to [ ● ] shares of Common Stock (the “Shares”).

William Blair & Company, L.L.C. hereby agrees to [release] [waive] the transfer restrictions set forth in the Lock-up Letter, but only with respect to the Shares, effective [ ● ], 2026; provided, however, that such [release] [waiver] is conditioned on the Company announcing the impending [release] [waiver] by press release through a major news service at least two business days before effectiveness of such [release] [waiver]. This letter will serve as notice to the Company of the impending [release] [waiver].

Except as expressly [released] [waived] hereby, the Lock-up Letter shall remain in full force and effect.

Yours very truly,

cc:

Company


Annex III

Form of Press Release

Deep Fission, Inc.
[Date]

Deep Fission, Inc. (“Company”) announced today that William Blair & Company, L.L.C., the lead book-running manager in the Company’s recent public sale of [ ● ] shares of common stock, is [releasing] [waiving] a lock-up restriction with respect to [ ● ] shares of the Company’s common stock held by [an officer or director] [certain officers or directors] of the Company. The [release] [waiver] will take effect on [ ● ], 2026, and the shares may be sold on or after such date.

This press release is not an offer for sale of the securities in the United States or in any other jurisdiction where such offer is prohibited, and such securities may not be offered or sold in the United States absent registration or an exemption from registration under the United States Securities Act of 1933, as amended.