SEC FORM 3

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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1. Name and Address of Reporting Person^*

van der Horst Edward

(Last)

(First)

(Middle)

C/O SENSEI BIOTHERAPEUTICS, INC.

451 D STREET, SUITE 710

(Street)

BOSTON

02210

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
12/07/2022

3. Issuer Name and Ticker or Trading Symbol
Sensei Biotherapeutics, Inc. [ SNSE ]

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

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

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	21,173⁽¹⁾	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock Option (Right to Buy)	⁽²⁾	08/28/2029	Common Stock	3,125	$16.32	D
Stock Option (Right to Buy)	⁽³⁾	08/04/2030	Common Stock	55,208	$3.22	D
Stock Option (Right to Buy)	⁽⁴⁾	01/26/2031	Common Stock	72,916	$19	D
Stock Option (Right to Buy)	⁽⁵⁾	10/30/2031	Common Stock	20,000	$8.69	D
Stock Option (Right to Buy)	⁽⁶⁾	02/14/2032	Common Stock	44,000	$4.3	D

Explanation of Responses:

1. Represents: (1) 14,700 restricted stock units (the "RSUs"), with each RSU representing a contingent right to receive one share of the Issuer's common stock, vesting in four equal annual installments on each of February 15, 2023, February 15, 2024, February 15, 2025 and February 15, 2026, subject to the Reporting Person's continuous service with the Issuer through such vesting date; and (2) 6,473 shares purchased by the Reporting Person pursuant to the Issuer's 2021 Employee Stock Purchase Plan.

2. 25% of the shares subject to the option vest on the first anniversary of the vesting commencement date, September 3, 2021, and 1/48th of the shares subject to the option vest monthly thereafter over 36 months, subject to Reporting Person's continuous service as of each such date.

3. 25% of the shares subject to the option vest on the first anniversary of the vesting commencement date, February 15, 2022, and 1/48th of the shares subject to the option vest monthly thereafter over 36 months, subject to Reporting Person's continuous service as of each such date.

4. 25% of the shares subject to the option vest on the first anniversary of the vesting commencement date, February 4, 2023, and 1/48th of the shares subject to the option vest monthly thereafter over 36 months, subject to Reporting Person's continuous service as of each such date.

5. 25% of the shares subject to the option vest on the first anniversary of the vesting commencement date, October 8, 2023, and 1/48th of the shares subject to the option vest monthly thereafter over 36 months, subject to Reporting Person's continuous service as of each such date.

6. 25% of the shares subject to the option vest on the first anniversary of the vesting commencement date, February 15, 2024, and 1/48th of the shares subject to the option vest monthly thereafter over 36 months, subject to Reporting Person's continuous service as of each such date.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Mark Ballantyne, Attorney-in-Fact	12/16/2022
	** 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 5 (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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.