SEC FORM 4

SEC FORM 4 SEC Form 4

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^*

Flaherty Keith T.

(Last)

(First)

(Middle)

C/O CHECKMATE PHARMACEUTICALS, INC.

245 MAIN STREET, 2ND FLOOR

(Street)

CAMBRIDGE

02142

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
Checkmate Pharmaceuticals, Inc. [ CMPI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
05/31/2022

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Stock Option (Right to Buy)	$6.27	05/31/2022		D⁽¹⁾			10,030	⁽¹⁾	06/16/2031	Common Stock	10,030	⁽¹⁾	0	D
Stock Option (Right to Buy)	$2.47	05/31/2022		D⁽¹⁾			4,012	⁽¹⁾	03/27/2028	Common Stock	4,012	⁽¹⁾	0	D
Stock Option (Right to Buy)	$2.62	05/31/2022		D⁽¹⁾			22,736	⁽¹⁾	03/27/2029	Common Stock	22,736	⁽¹⁾	0	D

Explanation of Responses:

1. At the effective time of the merger contemplated by the Agreement and Plan of Merger dated April 18, 2022, among Checkmate Pharmaceuticals, Inc. (the "Issuer"), Regeneron Pharmaceuticals, and Scandinavian Acquisition Sub, Inc. (the "Merger"), each option granted by the Issuer to purchase Issuer Common Stock, whether or not vested, which has a per share exercise price that is less than $10.50 (each, an "In the Money Issuer Option") that was outstanding and unexercised as of immediately prior to the effective time of the Merger was cancelled and automatically converted into the right to receive an amount in cash equal to the product of (1) the total number of Issuer Common Stock subject to such In the Money Issuer Option and (2) the excess of $10.50 over the exercise price of such In the Money Issuer Option, subject to any required withholding of taxes.

Remarks:

	/s/ Kleem Chaudhary, attorney-in-fact	05/31/2022
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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SEC Form 4 filed by Flaherty Keith T.