| Item 1. | |
| (a) | Name of issuer:
Sensei Biotherapeutics, Inc. |
| (b) | Address of issuer's principal executive offices:
1405 Research Boulevard, Suite 125, Rockville, Maryland 20850 |
| Item 2. | |
| (a) | Name of person filing:
ICS Opportunities II LLC
Millennium Management LLC
Millennium Group Management LLC
Israel A. Englander |
| (b) | Address or principal business office or, if none, residence:
ICS Opportunities II LLC
c/o Millennium Management LLC
399 Park Avenue
New York, New York 10022
Millennium Management LLC
399 Park Avenue
New York, New York 10022
Millennium Group Management LLC
399 Park Avenue
New York, New York 10022
Israel A. Englander
c/o Millennium Management LLC
399 Park Avenue
New York, New York 10022 |
| (c) | Citizenship:
ICS Opportunities II LLC - Cayman Islands
Millennium Management LLC - Delaware
Millennium Group Management LLC - Delaware
Israel A. Englander - United States |
| (d) | Title of class of securities:
Common Stock, par value $0.0001 per share |
| (e) | CUSIP No.:
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| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: |
| (a) |  Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
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| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
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| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
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| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
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| (e) | An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
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| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
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| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
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| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
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| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
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| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
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| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
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| | |
| Item 4. | Ownership |
| (a) | Amount beneficially owned:
See response to Item 9 on each cover page.
As of the close of business on February 24, 2026, the reporting persons beneficially owned an aggregate of 84,541 shares of common stock, par value $0.0001 per share ("Common Stock") or 6.7% of the Common Stock outstanding. After acquiring beneficial ownership of more than 10% of the outstanding Common Stock on March 26, 2026, the reporting persons beneficially owned 127,095 shares of Common Stock or 10.1% of the Common Stock outstanding. As of the close of business on May 14, 2026, the reporting persons beneficially owned an aggregate of 128,761 shares of Common Stock or 9.6% of the Common Stock outstanding. The information reported on each cover page is as of the close of business on May 14, 2026.
Calculations herein prior to May 14, 2026 are based on 1,261,290 shares of Common Stock outstanding as November 10, 2025, as reported by Sensei Biotherapeutics, Inc. (the "Company") on its 10-Q filed on November 14, 2025. Calculations as of May 14, 2026 are based on 1,341,140 shares of Common Stock outstanding as of April 13, 2026, as reported by the Company in the proxy statement filed on April 27, 2026. |
| (b) | Percent of class:
See response to Item 11 on each cover page. |
| (c) | Number of shares as to which the person has:
|
| | (i) Sole power to vote or to direct the vote:
See response to Item 5 on each cover page.
|
| | (ii) Shared power to vote or to direct the vote:
See response to Item 6 on each cover page.
|
| | (iii) Sole power to dispose or to direct the disposition of:
See response to Item 7 on each cover page.
|
| | (iv) Shared power to dispose or to direct the disposition of:
See response to Item 8 on each cover page.
The securities disclosed herein as potentially beneficially owned by Millennium Management LLC, Millennium Group Management LLC and Mr. Englander are held by entities subject to voting control and investment discretion by Millennium Management LLC and/or other investment managers that may be controlled by Millennium Group Management LLC (the managing member of Millennium Management LLC) and Mr. Englander (the sole voting trustee of the managing member of Millennium Group Management LLC). The foregoing should not be construed in and of itself as an admission by Millennium Management LLC, Millennium Group Management LLC or Mr. Englander as to beneficial ownership of the securities held by such entities.
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| Item 5. | Ownership of 5 Percent or Less of a Class. |
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Not Applicable
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| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. |
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Not Applicable
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| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. |
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Not Applicable
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| Item 8. | Identification and Classification of Members of the Group. |
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If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(K), so indicate under Item 3(k) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group.
See Exhibit I |
| Item 9. | Notice of Dissolution of Group. |
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Not Applicable
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Rule 13d-1(c)