DEEP FISSION, INC.

This section describes the compensation of our named executive officers and non-employee directors for the fiscal year ended December 31, 2025. The discussion below covers compensation arrangements of Legacy Deep Fission prior to the consummation of the Merger with Surfside and compensation arrangements of Deep Fission following the Merger, to the extent applicable, as well as compensation arrangements of Surfside prior to the consummation of the Merger.

Director Compensation

Ian Jacobs and Mark Tompkins served as our sole directors prior to the Merger and resigned from our Board effective as of the closing of the Merger, which occurred on September 5, 2025. Messrs. Jacobs and Tompkins did not receive any compensation for their service on our Board. Effective as of September 5, 2025, Elizabeth Muller and Richard Muller were appointed to our Board, although Dr. Muller resigned from the board of directors on November 7, 2025 to focus on his continuing responsibilities as our Chief Technology Officer. Jonathon Angell and Leslie Goldman Tepper were appointed to our Board on November 7, 2025 and Thomas Glanville and Blake Janover were appointed to our Board on December 19, 2025.

Ms. Muller is employed as our Chief Executive Officer and President and receives no compensation for her service as a director and chair of the board of directors. The compensation received by Ms. Muller as an employee is shown in “Executive Compensation - Summary Compensation Table” below. Dr. Muller and Messrs. Thompson and Jacobs each also served as executive officers during the fiscal year ended December 31, 2025 (and Dr. Muller continues to serve as our Chief Technology Officer) and their compensation is also shown in “Executive Compensation – Summary Compensation Table” below.

On November 7, 2025, the board of directors adopted a Non-Employee Director Compensation Policy. Under this policy, non-employee directors receive cash and equity compensation for their service. Annual cash retainers are paid for Board service and for service on a committee, and are paid quarterly in arrears.

The fees paid to our non-employee directors for service on our Board and for service on each committee of our Board of which the non-employee director is a member are as follows:

Annual Board Member Service Retainer

All non-employee directors: $67,500

Annual Committee Member Service Retainer

Member of the audit committee: $10,000

Member of the compensation committee: $9,500

Member of the nominating and corporate governance committee: $9,500

Equity compensation for non-employee directors is provided in the form of restricted stock units (“RSUs”) granted under the Company’s 2025 Equity Incentive Plan (the “2025 Plan”). Each RSU represents the right to receive one share of the Company’s common stock upon vesting. In connection with the adoption of the policy, the board of directors determined that all RSU awards made to non-employee directors will provide the holder with the ability, following vesting, to defer receipt of the underlying shares until the earlier of (i) a Change in Control (as defined in the 2025 EIP), and (ii) the director’s separation from service. Delivery of any deferred shares will be made in compliance with the 2025 Plan and Section 409A of the U.S. Internal Revenue Code of 1986, as amended (the “Code”).

Under the Non-Employee Director Compensation Policy, non-employee directors who joined the board of directors on or before December 31, 2025 were entitled to receive an RSU award covering 100,000 shares of the Company’s common stock. On November 7, 2025, the Compensation Committee approved an RSU award of 100,000 shares to each of Ms. Goldman Tepper and Mr. Angell pursuant to this provision. On December 19, 2025, the Compensation Committee approved an RSU award of 100,000 shares to each of Messrs. Glanville and Janover pursuant to this provision. In each case, although the RSU awards were approved by the Compensation Committee in fiscal year 2025, the vesting terms for such awards were not finalized until fiscal year 2026, and so the awards were not considered granted for purposes of ASC 718,Compensation – Stock Compensation, until March 31, 2026. As a result, in accordance with SEC rules, no value appears in the 2025 Nonemployee Director Compensation Table for such awards, and instead they will appear in our 2026 Nonemployee Director Compensation Table. The final vesting terms of the RSU awards provide that they will vest on the earlier of six months after the grant date and the occurrence of a Change in Control (as defined in the 2025 Plan).

Under the Non-Employee Director Compensation Policy, non-employee directors who join the board of directors after December 31, 2025 will receive an initial RSU award having a grant-date fair value of $130,000, which vests in full on the earlier of the one-year anniversary of the grant date and the occurrence of a Change in Control. Beginning with the 2026 annual meeting of stockholders, each non-employee director who continues to serve on the board of directors following the annual meeting will receive an annual RSU award having a grant-date fair value of $130,000, which vests in full on the earlier of the first anniversary of the grant date and the occurrence of a Change in Control.

All RSU awards are made pursuant to the terms of the 2025 Plan and the Company’s standard form of award agreement and are subject to the deferred-delivery election described above. The Company also reimburses non-employee directors for reasonable expenses incurred in connection with their service.

2025 Nonemployee Director Compensation Table

The table below shows the aggregate number of unvested stock awards held as of December 31, 2025 by each non-employee director, which does not reflect the 100,000 RSUs approved by the Compensation Committee to be granted to each of Messrs. Angell, Glanville and Janover and Ms. Goldman Tepper in fiscal year 2025, but which were not granted until fiscal year 2026.

Executive Compensation

As an “emerging growth company,” we have opted to comply with the executive compensation disclosure rules applicable to such companies, which allows us to provide reduced compensation disclosure. This section discusses the material components of the executive compensation program for the Company’s named executive officers who appear in the “—2025 Summary Compensation Table” below. In 2025, the “named executive officers” and their positions with the Company were as follows:

Summary Compensation Table

The following table sets forth information concerning the compensation earned by or paid to our named executive officers for the fiscal years ended December 31, 2025 and December 31, 2024.

Base Salaries

During the fiscal year ended December 31, 2025, the base salaries of our named executive officers were determined by our Board (and, following its formation, our Compensation Committee) based on each executive’s role, responsibilities, experience and performance.

During the fiscal year ended December 31, 2025, Ms. Muller’s annual base salary was increased from $400,000 to $475,000, effective December 9, 2025.

Mr. Basel was promoted to the position of Chief Operating Officer on October 6, 2025. Prior to this date, Mr. Basel served as the Company’s Vice President of Nuclear Programs, and his base salary reflected in the Summary Compensation Table reflects the aggregate salary he actually received in the fiscal year ended December 31, 2025 for his service in both roles. Mr. Thompson ceased employment during the fiscal year ended December 31, 2025 and his base salary reflected in the Summary Compensation Table reflects the actual salary he received for service through his date of termination.

Annual Bonuses

Annual cash bonuses are determined by our Compensation Committee, and, prior to such Committee’s formation, our board of directors. Annual cash bonuses are set at a level that is commensurate with the executive’s duties and authorities, contributions, prior experience and sustained performance and bonus outcomes are determined based on an overall assessment of Company performance, the executive’s performance and contributions, and other relevant factors. After evaluating the foregoing factors, the Committee determined to pay discretionary cash bonuses to Ms. Muller, Dr. Muller and Mr. Brasel for fiscal year 2025 of $60,000, $90,000 and $72,500, respectively.

Equity Awards

We use equity compensation to align the interests of our employees, including our executive officers, with those of our stockholders and to promote long-term retention. Equity awards are approved by our Board or, following its formation, our Compensation Committee.

Prior to the closing of the Merger, Legacy Deep Fission granted stock options to Ms. Muller and Dr. Muller representing 811,699 and 649,363 shares of Legacy Deep Fission common stock, respectively (on an as-converted basis), pursuant to its pre-Merger 2025 Equity Incentive Plan (the “Pre-Merger 2025 Plan”). The stock options granted to Ms. Muller and Dr. Muller have an exercise price of $3.00 per share and vest over a four-year vesting schedule, with 25% of the shares vesting on June 1, 2025 and the remaining shares vesting in equal monthly installments over the following 36 months, subject to the executive’s continued service through each vesting date. No additional awards will be granted under the Pre-Merger 2025 Plan following the closing of the Merger.

Following the Merger, the Company granted equity awards to certain of its named executive officers in the form of stock options and RSUs pursuant to the 2025 Plan. Stock options are granted with an exercise price per share no less than the fair market value of the Company’s common stock on the date of grant. Equity awards generally vest over multi-year periods and may be subject to accelerated vesting upon certain termination of employment or change in control events. Following the closing of the Merger, Ms. Muller received a grant of 183,150 stock options and 549,451 RSUs, each vesting 25% on the first anniversary of the date of grant (December 9, 2025) and with the remaining 75% subject to a monthly vesting schedule over the subsequent three-year period and Mr. Brasel received a grant of 70,000 stock options, 25% of which vests on October 6, 2026 and with the remaining 75% subject to a monthly vesting schedule over the subsequent three-year period. As described below under “Separation Agreement” Mr. Thompson also received an award of 72,753 fully vested shares of Legacy Deep Fission common stock in connection with his termination of employment.

Prior to the Merger, Legacy Deep Fission was not a public company and Surfside did not grant equity awards, so we did not have any policy or practice regarding the timing of awards of stock options in relation to the disclosure of material nonpublic information. Following the Merger, we have not yet had sufficient time to develop a practice of standard timing of granting equity awards, but when we grant stock options our Board or applicable committee approving the grant will determine that there is not material nonpublic information that would be released on or near the date of grant. Although we granted stock options to Mr. Brasel on November 7, 2025, which was one business day after and within four business days prior to the filing of current reports on Form 8-K, we are unable to determine the impact of such reports on the price of our common stock because our shares are not publicly listed and therefore there is no readily ascertainable value of our common stock. However, we do not consider the information disclosed in such reports as likely to have had a material impact on the price of our common stock.

Benefits

During the fiscal year ended December 31, 2025, we provided benefits to our named executive officers on the same basis as our other employees, including medical, dental, vision, life and AD&D, and short- and long-term disability insurance, flexible spending accounts, vacation and paid holidays. Our named executive officers are also eligible to participate in our 401(k) plan.

Other than director and officer insurance coverage that we maintain for our directors and officers, the Company does not provide material executive-specific health and welfare benefits or perquisites. We also do not provide employees, including our named executive officers, any other retirement benefits, including but not limited to tax-qualified defined benefit plans, supplemental executive retirement plans or nonqualified defined contribution plans.

Executive Compensation Arrangements

Each of the Company’s current named executive officers is an at-will employee, although we have provided Ms. Muller and Mr. Brasel with offer letters reflecting the key terms of their employment with us. The key terms of employment of each named executive officer, as in effect on December 31, 2025, are described below.

Chief Executive Officer — Elizabeth A. Muller

Ms. Muller’s employment is governed by an offer letter, effective December 9, 2025, pursuant to which she serves as the Company’s Chair, President, and Chief Executive Officer on an at-will basis. Ms. Muller receives an annual base salary of $475,000 and is eligible to receive an annual performance-based cash bonus with a target opportunity equal to 50% of her base salary.

In addition, Ms. Muller was granted equity awards consisting of (i) an option to purchase 183,150 shares of the Company’s common stock and (ii) 549,451 RSU’s, each of which vests monthly over a four-year period, subject to a one-year cliff and Ms. Muller’s continued service to the Company. The offer letter also provides that Ms. Muller is eligible to participate in the Company’s Executive Severance and Change in Control Policy, as described below. The terms of the offer letter were approved by the Company’s Compensation Committee.

Ms. Muller participates in the Company’s employee benefit programs on the same basis as other senior executives and is subject to the Company’s Proprietary Information & Intellectual Property Agreement.

Chief Technology Officer — Richard A. Muller

Dr. Muller serves as the Company’s Chief Technology Officer on an at-will basis. The Company has not entered into a written offer letter or employment agreement with Dr. Muller. He receives an annual base salary of $300,000 and is eligible for an annual performance-based cash bonus with a target opportunity equal to 30% of his base salary. His compensation, including any future adjustments or equity awards, is established from time to time by the board of directors and remains subject to approval by the Compensation Committee.

Dr. Muller participates in the Company’s employee benefit programs on the same basis as other senior executives and is subject to the Company’s Proprietary Information & Intellectual Property Agreement.

Chief Operating Officer — Michael Brasel

Mr. Brasel’s employment is governed by an offer letter, effective November 7, 2025, pursuant to which he serves as Chief Operating Officer on an at-will basis. Mr. Brasel receives an annual base salary of $300,000, subject to periodic review, and is eligible for an annual performance-based cash bonus with a target opportunity equal to 30% of his base salary.

In connection with his appointment, Mr. Brasel was granted an option to purchase 70,000 shares of the Company’s common stock at an exercise price equal to the fair market value on the date of grant, vesting over four years with a one-year cliff subject to Mr. Brasel’s continued service to the Company, and otherwise subject to the 2025 Plan and applicable award agreement.

Mr. Brasel participates in the Company’s employee benefit programs on the same basis as other senior executives and is subject to the Company’s Proprietary Information & Intellectual Property Agreement.

Separation Agreement

In connection with his cessation of employment during the fiscal year ended December 31, 2025, Legacy Deep Fission entered into a separation agreement with Mr. Thompson on September 4, 2025 (the “Separation Agreement”). Pursuant to the Separation Agreement, subject to Mr. Thompson releasing all claims against the Company, Legacy Deep Fission agreed, among other things, to pay Mr. Thompson a lump sum cash severance payment equal to three months of his base salary, less applicable payroll deductions and withholdings, to grant Mr. Thompson 72,753 fully vested shares of Legacy Deep Fission common stock, and to accelerate the vesting of 10,000 shares of previously granted Legacy Deep Fission common stock.

Potential Payments Upon Termination or Change in Control

The Compensation Committee adopted an Executive Severance and Change in Control Policy effective November 7, 2025. The policy provides severance protections for executive officers who are designated by the board of directors as eligible to participate; however, as of the date of this Annual Report on Form 10-K, Ms. Muller is the only executive officer designated as eligible to participate in the policy, and no executive officer is currently entitled to receive any benefits under the policy. Mr. Thompson’s separation was not governed by this policy.

The policy provides that, if an eligible executive’s employment is terminated by the Company without cause or the executive resigns for good reason, in each case, outside the context of a change in control of the Company, the executive would be eligible to receive severance benefits subject to the executive’s execution and non-revocation of a release of claims. These severance benefits include continued payment of base salary for six months, a pro-rated portion of the executive’s target annual bonus for the year of termination, and continued health-care coverage (or a cash equivalent) for up to six months. Unvested time-based equity awards would become vested with respect to the number of shares that would have vested had the executive remained employed for an additional six months, and performance-based equity awards would remain outstanding and eligible to vest in accordance with their original terms.

If an eligible executive’s employment is terminated by the Company without cause or the executive resigns for good reason, in each case, during the period beginning three months prior to a change in control and ending twelve months following the change in control, the policy provides enhanced severance benefits subject to the executive’s execution and non-revocation of a release of claims. In such circumstances, an eligible executive would receive a lump-sum payment equal to 18 months of base salary, a lump-sum payment equal to the executive’s annual target bonus, and continued health-care coverage (or a cash equivalent) for up to 18 months. Time-based equity awards would become fully vested, and performance-based equity awards would vest based on actual or target performance, as applicable under the policy and the terms of the governing award agreements.

The policy also includes a “best-net” cutback provision under Section 280G of the Code, pursuant to which parachute payments will be reduced only if doing so would result in a greater after-tax benefit to the executive. No tax gross-ups are provided.

Outstanding Equity Awards at Fiscal Year-End

The following table sets forth information regarding outstanding equity awards held by our named executive officers as of December 31, 2025, including unexercised stock options and unvested RSUs.

Mr. Jacobs resigned as an executive officer of the Company upon the closing of the Merger on September 5, 2025, and Mr. Thompson ceased employment on August 20, 2025. Neither Mr. Jacobs nor Mr. Thompson held any outstanding equity awards as of December 31, 2025, and accordingly, they are excluded from the table below.

Legacy Deep Fission’s 2025 Equity Incentive Plan (Pre-Merger) and Outstanding Awards Thereunder

Pursuant to the Merger Agreement and upon the closing of the Merger, we assumed the options issued pursuant to the Pre-Merger 2025 Plan (the “Assumed Options”). The exercise price per share of each Assumed Option is equal to the exercise price of the option immediately prior to the Effective Time (rounded up to the nearest whole cent). Each Assumed Option shall be subject to the terms and conditions of the Pre-Merger 2025 Plan until such outstanding options are exercised or until they terminate or expire by their terms. No further awards shall be made under the Pre-Merger 2025 Plan, and Deep Fission’s board or a committee thereof has succeeded to the authority and responsibility of Legacy Deep Fission’s board of directors or any committee thereof with respect to each Assumed Option.

Our 2025 Equity Incentive Plan (Post-Merger)

Pursuant to the Merger Agreement and immediately prior to the closing of the Merger, we adopted the 2025 Plan, which provides for the issuance of incentive awards consisting of stock options, restricted stock awards, RSUs, stock appreciation rights, performance awards, cash awards and stock bonus awards. We have initially reserved 9,500,884 shares of the Company’s common stock for future issuances of incentive awards under the 2025 Plan at the discretion of our Board to officers, employees, consultants and directors. The number of shares reserved for issuance under our 2025 Plan will increase automatically on January 1 of each calendar year for a period of up to nine years, beginning on January 1, 2027 and continuing through and including January 1, 2035, in an amount equal to the lesser of (i) 5% of the shares of Common Stock outstanding on the last day of the immediately preceding calendar year, and (ii) such lesser amount as determined by the board of directors in its discretion.

Our 2025 Employee Stock Purchase Plan

Pursuant to the Merger and immediately prior to the closing of the Merger, we adopted our 2025 Employee Stock Purchase Plan (the “2025 ESPP”), which allows for eligible U.S. employees to purchase our common shares in a manner that may qualify for favorable tax treatment under Section 423 of the Code. The 2025 ESPP will also permit the grant of purchase rights that do not qualify for such favorable tax treatment in order to allow deviations necessary to permit participation by eligible employees who are foreign nationals or employed outside of the U.S. while complying with applicable foreign laws. We have initially reserved 1,000,000 shares of common stock for issuance under the 2025 ESPP. Shares issuable under the 2025 ESPP may be shares of authorized but unissued or reacquired common stock, including shares purchased by the Company on the open market. The number of shares of our common stock reserved for issuance under the 2025 ESPP will increase automatically on January 1 of each calendar year for a period of up to nine years, beginning on January 1, 2027 and continuing through and including January 1, 2035, in an amount equal to the lesser of (i) 1% of the total number of shares of our common stock outstanding on the last day of the immediately preceding calendar year, (ii) 2,000,000 shares and (iii) such lesser amount as determined by the board of directors in its discretion. As of the date hereof, no shares of our common stock have been purchased under the 2025 ESPP.