FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person *
McCallum Sophie

(Last) (First) (Middle)
C/O DEEP ISOLATION NUCLEAR, INC.
5717 LEGACY DRIVE, STE 250, OFFICE 2079

(Street)
PLANO TX 75024

(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Deep Isolation Nuclear, Inc. [ DBHL ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
Chief of Staff
3. Date of Earliest Transaction (Month/Day/Year)
10/06/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock (1) 10/06/2026   A   40,179 A $ 0 56,846 D  
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy) (2) $ 3.5 10/06/2026   A   62,206     (2) 09/29/2036 Common Stock 62,206 $ 0 62,206 D  
Stock Option (right to buy) (2) $ 3.5 10/06/2026   A   2,301     (3) 09/29/2036 Common Stock 2,301 $ 0 2,301 D  
Explanation of Responses:
1. Represents a grant of restricted stock units ("RSUs") to the Reporting Person pursuant to the Deep Isolation Nuclear, Inc. 2025 Equity Incentive Plan. Each RSU represents a contingent right to receive one share of common stock upon vesting. The RSUs shall vest as follows: 10,045 RSUs on September 29, 2027, 10,045 RSUs on September 29, 2028, 10,044 RSUs on September 29, 2029 and 10,045 RSUs on September 29, 2030, in each case subject to the Reporting Person's continued service through each vesting date.
2. Represents a grant of incentive stock option pursuant to the Deep Isolation Nuclear, Inc. 2025 Equity Incentive Plan. The option shall vest as follows: 16,127 option shares on September 29, 2027, 1,344 option shares on October 29, 2027, 386 option shares on November 29, 2027, and the remaining option shares in monthly installments on the 29th day of each month (or the last day of the month, if earlier) from January 29, 2028 through September 29, 2030, in each case subject to the Reporting Person's continued service through each vesting date.
3. Represents a grant of non-qualified stock option pursuant to the Deep Isolation Nuclear, Inc. 2025 Equity Incentive Plan. The option shall vest as follows: 958 option shares on November 29, 2027 and 1,343 option shares on December 29, 2027, in each case subject to the Reporting Person's continued service through each vesting date.
/s/ Sophie McCallum 10/08/2026
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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