James Peyer - 09 Dec 2025 Form 4 Insider Report for Sensei Biotherapeutics, Inc. (SNSE)

Reporting relationship: Other*, 10%+ Owner
Issuer ticker: SNSE
Reported as of: 09 Dec 2025
Net transaction value: -$52,047
SEC form: 4
Accepted by SEC: 10 Dec 2025, 16:52:32 UTC
Prior SEC filing: 08 Dec 2025
Next SEC filing: 01 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ James Peyer

Key filing fact

James Peyer filed Form 4 for Sensei Biotherapeutics, Inc. (SNSE) on 10 Dec 2025.

Key facts

This page summarizes James Peyer's Form 4 filing for Sensei Biotherapeutics, Inc. (SNSE).
6 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 10 Dec 2025, 16:52.

Change

Previous filing in this sequence was filed on 08 Dec 2025.
Current net transaction value: -$52,047.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001843594 Primary reporting owner

Peyer James

Relationship: Other*, 10%+ Owner
Address: 228 PARK AVENUE S., #66643, NEW YORK
Signature: /s/ James Peyer
Signature date: 10 Dec 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

SNSE transaction

Common Stock

Sale

Transaction value: $26,672
Shares: -3,105
Change %: -1.9%
Price: $8.59
Shares after: 158,254
Date: 08 Dec 2025
Ownership: See footnote
Footnotes: F1, F2

SNSE transaction

Common Stock

Sale

Transaction value: $21,195
Shares: -2,666
Change %: -1.7%
Price: $7.95
Shares after: 155,588
Date: 09 Dec 2025
Ownership: See footnote
Footnotes: F2, F3

SNSE transaction

Common Stock

Options Exercise

Transaction value: $2,528
Shares: +395
Change %: +0.25%
Price: $6.40
Shares after: 155,983
Date: 09 Dec 2025
Ownership: See footnote
Footnotes: F2

SNSE transaction

Common Stock

Sale

Transaction value: $3,176
Shares: -395
Change %: -0.25%
Price: $8.04
Shares after: 155,588
Date: 09 Dec 2025
Ownership: See footnote
Footnotes: F2

SNSE transaction

Common Stock

Sale

Transaction value: $3,532
Shares: -446
Change %: -0.29%
Price: $7.92
Shares after: 155,142
Date: 09 Dec 2025
Ownership: See footnote
Footnotes: F2, F4

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

SNSE transaction Derivative

Stock Option (Right to Buy)

Options Exercise

Transaction value: $0
Shares: -395
Change %: -100%
Price: $0.000000
Shares after: 0
Date: 09 Dec 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 395
Exercise price: $6.40
Footnotes: F5, F6

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 6 footnotes

Footnote F1

The price reported in Column 4 is a weighted average price. The prices sold ranged from $8.50 to $9.00. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.

Footnote F2

These shares are held by Cambrian Biopharma Inc, a Delaware corporation ("Cambrian"). The Reporting Person is the Chief Executive Officer of Cambrian and in such capacity may direct the voting and disposition of the shares held by Cambrian, subject in certain instances to the approval of Cambrian's Board of Directors. Mr. Peyer disclaims beneficial ownership of such shares.

Footnote F3

The price reported in Column 4 is a weighted average price. The prices sold ranged from $7.80 to $8.33. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.

Footnote F4

The price reported in Column 4 is a weighted average price. The prices sold ranged from $7.91 to $7.95. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.

Footnote F5

The amount shown reflects the number of shares held following the reported transaction, as adjusted for a 1-for-20 stock split effectuated by the issuer.

Footnote F6

The shares subject to the option vest and become exercisable in 12 equal monthly installments over a one year period such that the option is fully vested on the first anniversary of the date of grant, or May 21, 2026, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date; provided that the option will in any case be fully vested on the date of the Company's next annual stockholder meeting, subject to the Reporting Person's continuous service with the Issuer through such vesting date.