MILLENNIUM MANAGEMENT LLC - 02 Apr 2026 Form 4 Insider Report for Sensei Biotherapeutics, Inc. (SNSE)

Reporting relationship: 10%+ Owner
Issuer ticker: SNSE
Reported as of: 02 Apr 2026
Net transaction value: -$396,750
SEC form: 4
Accepted by SEC: 15 May 2026, 16:24:06 UTC
Prior SEC filing: 15 May 2026
Source filing: View source filing
Reporting owner signature: MILLENNIUM MANAGEMENT LLC: By: /s/ Gil Raviv, Global General Counsel

Key filing fact

MILLENNIUM MANAGEMENT LLC filed Form 4 for Sensei Biotherapeutics, Inc. (SNSE) on 15 May 2026.

Key facts

This page summarizes MILLENNIUM MANAGEMENT LLC's Form 4 filing for Sensei Biotherapeutics, Inc. (SNSE).
17 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 15 May 2026, 16:24.

Change

Previous filing in this sequence was filed on 15 May 2026.
Current net transaction value: -$396,750.

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 (4)

CIK 0001273087 Primary reporting owner

MILLENNIUM MANAGEMENT LLC

Relationship: 10%+ Owner
Address: 399 PARK AVENUE, NEW YORK
Signature: MILLENNIUM MANAGEMENT LLC: By: /s/ Gil Raviv, Global General Counsel
Signature date: 14 May 2026

CIK 0001783647

ICS OPPORTUNITIES II LLC

Relationship: 10%+ Owner
Address: C/O MILLENNIUM MANAGEMENT LLC, 399 PARK AVENUE, NEW YORK
Signature: ICS OPPORTUNITIES II LLC, By: Millennium Management LLC, its Investment Manager: By: /s/ Gil Raviv, Global General Counsel
Signature date: 14 May 2026

CIK 0001446830

MILLENNIUM GROUP MANAGEMENT LLC

Relationship: 10%+ Owner
Address: 399 PARK AVENUE, NEW YORK
Signature: MILLENNIUM GROUP MANAGEMENT LLC: By: /s/ Gil Raviv, Global General Counsel
Signature date: 14 May 2026

CIK 0001017456

ENGLANDER ISRAEL A

Relationship: 10%+ Owner
Address: C/O MILLENNIUM MANAGEMENT LLC, 399 PARK AVENUE, NEW YORK
Signature: /s/ Israel A. Englander
Signature date: 14 May 2026

Reported non-derivative transactions

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

SNSE transaction

Common Stock

Purchase

Transaction value: $870
Shares: +26
Change %: +0.02%
Price: $33.47
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F1, F2, F3

SNSE transaction

Common Stock

Purchase

Transaction value: $870
Shares: +26
Change %: +0.02%
Price: $33.47
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F1, F2, F3

SNSE transaction

Common Stock

Purchase

Transaction value: $870
Shares: +26
Change %: +0.02%
Price: $33.47
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F1, F2, F3

SNSE transaction

Common Stock

Purchase

Transaction value: $870
Shares: +26
Change %: +0.02%
Price: $33.47
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F1, F2, F3

SNSE transaction

Common Stock

Purchase

Transaction value: $44,344
Shares: +1,276
Change %: +0.89%
Price: $34.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F4

SNSE transaction

Common Stock

Purchase

Transaction value: $44,344
Shares: +1,276
Change %: +0.89%
Price: $34.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F4

SNSE transaction

Common Stock

Purchase

Transaction value: $44,344
Shares: +1,276
Change %: +0.89%
Price: $34.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F4

SNSE transaction

Common Stock

Purchase

Transaction value: $44,344
Shares: +1,276
Change %: +0.89%
Price: $34.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F4

SNSE transaction

Common Stock

Purchase

Transaction value: $24,919
Shares: +701
Change %: +0.49%
Price: $35.55
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F5

SNSE transaction

Common Stock

Purchase

Transaction value: $24,919
Shares: +701
Change %: +0.49%
Price: $35.55
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F5

SNSE transaction

Common Stock

Purchase

Transaction value: $24,919
Shares: +701
Change %: +0.49%
Price: $35.55
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F5

SNSE transaction

Common Stock

Purchase

Transaction value: $24,919
Shares: +701
Change %: +0.49%
Price: $35.55
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F5

SNSE transaction

Common Stock

Sale

Transaction value: $95,647
Shares: -3,099
Change %: -2.1%
Price: $30.86
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F6

SNSE transaction

Common Stock

Sale

Transaction value: $95,647
Shares: -3,099
Change %: -2.1%
Price: $30.86
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F6

SNSE transaction

Common Stock

Sale

Transaction value: $95,647
Shares: -3,099
Change %: -2.1%
Price: $30.86
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F6

SNSE transaction

Common Stock

Sale

Transaction value: $95,647
Shares: -3,099
Change %: -2.1%
Price: $30.86
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F6

SNSE transaction

Common Stock

Sale

Transaction value: $40,165
Shares: -1,265
Change %: -0.87%
Price: $31.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F7

SNSE transaction

Common Stock

Sale

Transaction value: $40,165
Shares: -1,265
Change %: -0.87%
Price: $31.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F7

SNSE transaction

Common Stock

Sale

Transaction value: $40,165
Shares: -1,265
Change %: -0.87%
Price: $31.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F7

SNSE transaction

Common Stock

Sale

Transaction value: $40,165
Shares: -1,265
Change %: -0.87%
Price: $31.75
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F7

SNSE transaction

Common Stock

Sale

Transaction value: $58,492
Shares: -1,794
Change %: -1.2%
Price: $32.60
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F8

SNSE transaction

Common Stock

Sale

Transaction value: $58,492
Shares: -1,794
Change %: -1.2%
Price: $32.60
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F8

SNSE transaction

Common Stock

Sale

Transaction value: $58,492
Shares: -1,794
Change %: -1.2%
Price: $32.60
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F8

SNSE transaction

Common Stock

Sale

Transaction value: $58,492
Shares: -1,794
Change %: -1.2%
Price: $32.60
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F8

SNSE transaction

Common Stock

Sale

Transaction value: $12,472
Shares: -374
Change %: -0.26%
Price: $33.35
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F9

SNSE transaction

Common Stock

Sale

Transaction value: $12,472
Shares: -374
Change %: -0.26%
Price: $33.35
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F9

SNSE transaction

Common Stock

Sale

Transaction value: $12,472
Shares: -374
Change %: -0.26%
Price: $33.35
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F9

SNSE transaction

Common Stock

Sale

Transaction value: $12,472
Shares: -374
Change %: -0.26%
Price: $33.35
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F9

SNSE transaction

Common Stock

Sale

Transaction value: $39,464
Shares: -1,134
Change %: -0.78%
Price: $34.80
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F10

SNSE transaction

Common Stock

Sale

Transaction value: $39,464
Shares: -1,134
Change %: -0.78%
Price: $34.80
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F10

SNSE transaction

Common Stock

Sale

Transaction value: $39,464
Shares: -1,134
Change %: -0.78%
Price: $34.80
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F10

SNSE transaction

Common Stock

Sale

Transaction value: $39,464
Shares: -1,134
Change %: -0.78%
Price: $34.80
Shares after: 144,974
Date: 02 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F10

SNSE transaction

Common Stock

Purchase

Transaction value: $34,246
Shares: +1,104
Change %: +0.79%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F11

SNSE transaction

Common Stock

Purchase

Transaction value: $34,246
Shares: +1,104
Change %: +0.79%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F11

SNSE transaction

Common Stock

Purchase

Transaction value: $34,246
Shares: +1,104
Change %: +0.79%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F11

SNSE transaction

Common Stock

Purchase

Transaction value: $34,246
Shares: +1,104
Change %: +0.79%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F11

SNSE transaction

Common Stock

Sale

Transaction value: $37,662
Shares: -1,214
Change %: -0.85%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F12

SNSE transaction

Common Stock

Sale

Transaction value: $37,662
Shares: -1,214
Change %: -0.85%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F12

SNSE transaction

Common Stock

Sale

Transaction value: $37,662
Shares: -1,214
Change %: -0.85%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F12

SNSE transaction

Common Stock

Sale

Transaction value: $37,662
Shares: -1,214
Change %: -0.85%
Price: $31.02
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F12

SNSE transaction

Common Stock

Sale

Transaction value: $1,438
Shares: -45
Change %: -0.03%
Price: $31.96
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F13

SNSE transaction

Common Stock

Sale

Transaction value: $1,438
Shares: -45
Change %: -0.03%
Price: $31.96
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F13

SNSE transaction

Common Stock

Sale

Transaction value: $1,438
Shares: -45
Change %: -0.03%
Price: $31.96
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F13

SNSE transaction

Common Stock

Sale

Transaction value: $1,438
Shares: -45
Change %: -0.03%
Price: $31.96
Shares after: 141,029
Date: 06 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F13

SNSE transaction

Common Stock

Purchase

Transaction value: $36,985
Shares: +1,108
Change %: +0.83%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F14

SNSE transaction

Common Stock

Purchase

Transaction value: $36,985
Shares: +1,108
Change %: +0.83%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F14

SNSE transaction

Common Stock

Purchase

Transaction value: $36,985
Shares: +1,108
Change %: +0.83%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F14

SNSE transaction

Common Stock

Purchase

Transaction value: $36,985
Shares: +1,108
Change %: +0.83%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F14

SNSE transaction

Common Stock

Sale

Transaction value: $61,212
Shares: -2,115
Change %: -1.6%
Price: $28.94
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F15

SNSE transaction

Common Stock

Sale

Transaction value: $61,212
Shares: -2,115
Change %: -1.6%
Price: $28.94
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F15

SNSE transaction

Common Stock

Sale

Transaction value: $61,212
Shares: -2,115
Change %: -1.6%
Price: $28.94
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F15

SNSE transaction

Common Stock

Sale

Transaction value: $61,212
Shares: -2,115
Change %: -1.6%
Price: $28.94
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F15

SNSE transaction

Common Stock

Sale

Transaction value: $6,091
Shares: -205
Change %: -0.15%
Price: $29.71
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F16

SNSE transaction

Common Stock

Sale

Transaction value: $6,091
Shares: -205
Change %: -0.15%
Price: $29.71
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F16

SNSE transaction

Common Stock

Sale

Transaction value: $6,091
Shares: -205
Change %: -0.15%
Price: $29.71
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F16

SNSE transaction

Common Stock

Sale

Transaction value: $6,091
Shares: -205
Change %: -0.15%
Price: $29.71
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F16

SNSE transaction

Common Stock

Sale

Transaction value: $138,813
Shares: -4,423
Change %: -3.2%
Price: $31.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F17

SNSE transaction

Common Stock

Sale

Transaction value: $138,813
Shares: -4,423
Change %: -3.2%
Price: $31.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F17

SNSE transaction

Common Stock

Sale

Transaction value: $138,813
Shares: -4,423
Change %: -3.2%
Price: $31.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F17

SNSE transaction

Common Stock

Sale

Transaction value: $138,813
Shares: -4,423
Change %: -3.2%
Price: $31.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F17

SNSE transaction

Common Stock

Sale

Transaction value: $9,674
Shares: -300
Change %: -0.22%
Price: $32.25
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F18

SNSE transaction

Common Stock

Sale

Transaction value: $9,674
Shares: -300
Change %: -0.22%
Price: $32.25
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F18

SNSE transaction

Common Stock

Sale

Transaction value: $9,674
Shares: -300
Change %: -0.22%
Price: $32.25
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F18

SNSE transaction

Common Stock

Sale

Transaction value: $9,674
Shares: -300
Change %: -0.22%
Price: $32.25
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F18

SNSE transaction

Common Stock

Sale

Transaction value: $36,985
Shares: -1,108
Change %: -0.82%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F19

SNSE transaction

Common Stock

Sale

Transaction value: $36,985
Shares: -1,108
Change %: -0.82%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F19

SNSE transaction

Common Stock

Sale

Transaction value: $36,985
Shares: -1,108
Change %: -0.82%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F19

SNSE transaction

Common Stock

Sale

Transaction value: $36,985
Shares: -1,108
Change %: -0.82%
Price: $33.38
Shares after: 133,986
Date: 07 Apr 2026
Ownership: See Footnote
Footnotes: F2, F3, F19

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

Additional SEC filing notes

Filing notes and footnotes

Section 16 status

MILLENNIUM MANAGEMENT LLC is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may still apply in specific circumstances.

Explanation of responses 19 footnotes

Footnote F1

Represents volume-weighted average price ("VWAP") of purchases of 26 shares of common stock ("Common Stock"), par value $0.0001 per share, of Sensei Biotherapeutics, Inc. (the "Company") on April 2, 2026 at prices ranging from $32.90 to $33.62. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting persons will provide full information regarding the number of shares purchased or sold by the reporting person at each separate price within each range represented by a VWAP disclosed herein.

Footnote F2

In each case, the number of shares of the Company's Common Stock disclosed in column 5 is the number of shares of the Company's Common Stock beneficially owned by Millennium Management LLC at the conclusion of the transactions on the date disclosed in the corresponding entry in column 2.

Footnote F3

The transactions in the Company's Common Stock reported herein were made by ICS Opportunities II LLC or other trading entities, in each case subject to voting control and investment discretion by Millennium Management LLC, Millennium Group Management LLC (the managing member of Millennium Management LLC) and Israel A. Englander (the sole voting trustee of the managing member of Millennium Group Management LLC). Each reporting person disclaims beneficial ownership of the shares of the Company's Common Stock disclosed herein except to the extent of such reporting person's pecuniary interest therein, if any.

Footnote F4

Represents VWAP of purchases of 1,276 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $33.97 to $34.90.

Footnote F5

Represents VWAP of purchases of 701 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $35.4481 to $35.91.

Footnote F6

Represents VWAP of sales of 3,099 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $30.1332 to $31.1212.

Footnote F7

Represents VWAP of sales of 1,265 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $31.21 to $32.15.

Footnote F8

Represents VWAP of sales of 1,794 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $32.22 to $33.1251.

Footnote F9

Represents VWAP of sales of 374 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $33.23 to $33.45.

Footnote F10

Represents VWAP of sales of 1,134 shares of the Company's Common Stock on April 2, 2026 at prices ranging from $34.40 to $35.25.

Footnote F11

Represents purchases of 1,104 shares of the Company's Common Stock on April 6, 2026 at $31.02 per share.

Footnote F12

Represents VWAP of sales of 1,214 shares of the Company's Common Stock on April 6, 2026 at prices ranging from $30.64 to $31.345.

Footnote F13

Represents VWAP of sales of 45 shares of the Company's Common Stock on April 6, 2026 at prices ranging from $31.80 to $32.17.

Footnote F14

Represents VWAP of purchases of 1,108 shares of the Company's Common Stock on April 7, 2026 at $33.38 per share.

Footnote F15

Represents VWAP of sales of 2,115 shares of the Company's Common Stock on April 7, 2026 at prices ranging from $28.5071 to $29.3167.

Footnote F16

Represents VWAP of sales of 205 shares of the Company's Common Stock on April 7, 2026 at prices ranging from $29.695 to $30.50.

Footnote F17

Represents VWAP of sales of 4,423 shares of the Company's Common Stock on April 7, 2026 at prices ranging from $30.9852 to $31.813.

Footnote F18

Represents VWAP of sales of 300 shares of the Company's Common Stock on April 7, 2026 at prices ranging from $32.0625 to $32.615.

Footnote F19

Represents sales of 1,108 shares of the Company's Common Stock on April 7, 2026 at $33.38 per share.

SEC remarks

Assuming, without conceding, the application of Section 16(b) of the Securities Exchange Act of 1934, the reporting persons have disgorged to the Company all amounts that could be deemed profit realized by them from the transactions in the Company's Common Stock reported on this Form 4 and the other two statements on Form 4 filed by Millennium Management LLC on the same date.