[Form 3] Sensei Biotherapeutics, Inc. Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

Sensei Biotherapeutics, Inc. (SNSE) reported the initial shareholdings of its President and Principal Executive Officer as of 11/14/2025. The executive directly beneficially owns 1,574 shares of common stock, primarily in the form of restricted stock units, with 1,444 shares already vested and 130 shares scheduled to vest in two equal installments on February 15, 2026 and February 15, 2027, subject to continued service.

The executive also holds multiple stock options to purchase common stock with different exercise prices and vesting schedules. These options cover separate grants that generally vest monthly over thirty-six months from their respective commencement dates, with one grant vesting 100% on December 1, 2025, all conditioned on continued service with Sensei Biotherapeutics.

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^*

Gerry Christopher

(Last) (First) (Middle)

C/O SENSEI BIOTHERAPEUTICS, INC.

1405 RESEARCH BLVD, SUITE 125

(Street)

ROCKVILLE MD 20850

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
11/14/2025

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)
	President & PEO

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	1,574(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)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	(2)	07/29/2032	Common Stock	3,750	$38.2	D
Sock Option (Right to Buy)	(3)	02/15/2033	Common Stock	1,100	$28.6	D
Sock Option (Right to Buy)	(4)	02/15/2034	Common Stock	5,881	$15.702	D
Sock Option (Right to Buy)	(5)	12/20/2034	Common Stock	4,999	$9	D
Sock Option (Right to Buy)	(6)	02/14/2035	Common Stock	2,500	$9.52	D

Explanation of Responses:

1. These shares represent restricted stock units (the "RSUs"). Each RSU represents a contingent right to receive one share of the common stock of the Issuer. 1,444 of the shares underlying the RSUs have fully vested and the remaining 130 shares vest in two equal installments on February 15, 2026 and February 15, 2027, in each case subject to the Reporting Person's continuous service with the Issuer through each such vesting date.

2. The shares subject to the option vest monthly over thirty-six (36) months from the vesting commencement date, July 18, 2022, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date.

3. The shares subject to the option vest monthly over thirty-six (36) months from the vesting commencement date, February 15, 2023, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date.

4. The shares subject to the option vest monthly over thirty-six (36) months from the vesting commencement date, February 15, 2024, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date.

5. 100% of the shares subject to the option shall vest on December 1, 2025, subject to the Reporting Person's continuous service with the Issuer as of such date.

6. The shares subject to the option vest monthly over thirty-six (36) months from the vesting commencement date, February 14, 2025, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Christopher Gerry	11/24/2025
	** 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).
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