Sophie McCallum - 23 Jul 2025 Form 3 Insider Report for Deep Isolation Nuclear, Inc.

Role: Chief of Staff, Corp. Sec.
Signature: /s/ Sophie McCallum
Transactions as of: 23 Jul 2025
Transactions value $: $0
Form type: 3
Filing time: 09 Sep 2025, 16:52:34 UTC
Next filing: 03 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
McCallum Sophie	Chief of Staff, Corp. Sec.	C/O DEEP ISOLATION NUCLEAR, INC., 2001 ADDISON STREET, SUITE 300, BERKELEY	/s/ Sophie McCallum	09 Sep 2025	0002085363

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Class	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	129K	$0.05	Direct	F1, F2
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	129K	$0.05	Direct	F3, F4
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	25.8K	$0.19	Direct	F5, F6
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	22.6K	$0.19	Direct	F7, F8
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	22.6K	$0.19	Direct	F9, F10
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	22.6K	$0.20	Direct	F11, F12
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	194K	$0.18	Direct	F13, F14
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	77.5K	$0.18	Direct	F15, F16
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	12.9K	$0.18	Direct	F17, F18
holding	Stock Option (Right to Buy)	23 Jul 2025	Common Stock	139K	$0.20	Direct	F19, F20

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The option fully vested as of February 15, 2022.
F2	Received in accordance with the terms of the Merger Agreement (as defined herein), in exchange for outstanding options to acquire 5,000 shares of Deep Isolation, Inc. ("Deep Isolation") common stock at an exercise price of $1.35 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Issuer's merger (the "Merger"), with Deep Isolation, the number of shares of Deep Isolation common stock subject to each outstanding but unexercised option to purchase Deep Isolation common stock (each such option, an "Outstanding Option," and such number of shares of Deep Isolation common stock subject to such Outstanding Option, the "option shares") was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by 25.837283 (the "Conversion Ratio"), rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F3	The option fully vested as of October 19, 2022.
F4	Received in connection with the Merger in accordance with the terms of the Agreement and Plan of Merger and Reorganization dated as of July 23, 2025, by and among the Issuer (f/k/a Aspen-1 Acquisition Inc.), Deep Isolation Acquisition Corp. and Deep Isolation (the "Merger Agreement") in exchange for Outstanding Options to acquire 5,000 shares of Deep Isolation common stock at an exercise price of $1.35 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F5	The option fully vested as of January 1, 2025.
F6	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 1,000 shares of Deep Isolation common stock at an exercise price of $4.88 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F7	The option fully vested as of August 15, 2024.
F8	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 875 shares of Deep Isolation common stock at an exercise price of $4.88 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F9	In accordance with the terms of the Merger Agreement and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board approved the accelerated vesting of all Outstanding Options previously issued under Deep Isolation's 2018 Equity Incentive Plan (the "2018 EIP"). Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares vested as of August 15, 2022 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date.
F10	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 875 shares of Deep Isolation common stock at an exercise price of $4.88 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F11	In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 EIP, including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares vested as of August 15, 2023 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date.
F12	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 875 shares of Deep Isolation common stock at an exercise price of $5.20 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F13	In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 EIP, including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares vested as of February 2, 2024 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date.
F14	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 7,500 shares of Deep Isolation common stock at an exercise price of $4.61 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F15	In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 EIP, including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares vested as of June 1, 2025 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date.
F16	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 3,000 shares of Deep Isolation common stock at an exercise price of $4.61 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F17	In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 EIP, including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 1/48th of the option shares vested monthly over a 48-month period beginning on May 1, 2024, subject to the Reporting Person's continued service through each vesting date.
F18	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 500 shares of Deep Isolation common stock at an exercise price of $4.61 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.
F19	In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 EIP, including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares were scheduled to vest as of April 1, 2026 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date.
F20	Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for Outstanding Options to acquire 5,375 shares of Deep Isolation common stock at an exercise price of $5.13 per share. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent.