Sec Form 4 Filing - GORDON MICHAEL S @ ProMIS Neurosciences Inc. - 2025-03-13

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person GORDON MICHAEL S 2. Issuer Name and Ticker or Trading Symbol ProMIS Neurosciences Inc. [ PMN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) See Remarks section. (Last) (First) (Middle) C/O TROVE,, 40 BROAD STREET, 8TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 03/13/2025 (Street) BOSTON, MA02109 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 Shares, no par value 03/13/2025 J( 1 ) 48,333 D 0 I By Title 19 Acies ( 2 ) Common Shares, no par value 2,435,029 I By Title 19 Promis ( 3 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other GORDON MICHAEL S C/O TROVE, 40 BROAD STREET, 8TH FLOOR BOSTON, MA02109 See Remarks section. Signatures /s/ Michael S. Gordon 08/14/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On March 13, 2025, the ownership of Title 19 Acies, a series of a Delaware limited liability company, was assigned to Skye Peak Partners LLC, a Delaware limited liability company ("SPP"), effective as of January 1, 2025. In connection with such assignment, the management of Title 19 Acies changed from the Reporting Person as sole manager to Emmett Gordon and Michael Youniss as managers, and the Reporting Person does not otherwise have investment control over the shares of the Issuer held by SPP. Accordingly, the Reporting Person no longer has a pecuniary interest in shares of the Issuer held by Title 19 Acies. ( 2 )By Title 19 Acies, of which the Reporting Person was the sole manager. ( 3 )By Title 19 Promis, a series of a Delaware limited liability company, of which the Reporting Person is the sole manager.

Remarks: The Issuer's Form 10-Q filed on August 13, 2025 provides that as of such date, the Issuer had 51,806,497 Common Shares outstanding. Based on this number and other shares included in the denominator of the calculation of the Reporting Person's ownership, the Reporting Person's ownership has dropped below 10% as of the date of filing this late Form 4. However, based on the publicly available number of outstanding shares reported prior to when this Form 4 was due, the Reporting Person held more than 10% at such time the Form 4 was due.

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).

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