Millennium entities disclose 127,095 Sensei Biotherapeutics (SNSE) shares

Rhea-AI Filing Summary

Sensei Biotherapeutics, Inc. insider filings show Millennium-affiliated entities as significant indirect holders of Common Stock. A total of 127,095 shares were reported as indirectly owned, including 126,828 shares held by ICS Opportunities II LLC and 267 shares held by other trading entities under Millennium Management LLC’s voting control. The reporting persons, including Millennium Group Management LLC and Israel A. Englander, disclaim beneficial ownership of these shares except to the extent of any pecuniary interest.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider MILLENNIUM MANAGEMENT LLC, ICS OPPORTUNITIES II LLC, MILLENNIUM GROUP MANAGEMENT LLC, ENGLANDER ISRAEL A

Role 10% Owner | 10% Owner | 10% Owner | 10% Owner

Type	Security	Shares	Price	Value
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 127,095 shares (Indirect, See Footnote)

Footnotes (2)

1. F1. The shares of Sensei Biotherapeutics, Inc. (the "Company") common stock ("Common Stock"), par value $0.0001 per share, disclosed herein were held 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).
2. F2. ICS Opportunities II LLC held 126,828 shares of the Company's Common Stock. Other trading entities subject to voting control and investment discretion by Millennium Management LLC held an aggregate of 267 shares of the Company's Common Stock. 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.

Key Figures

Indirect Common Stock holdings: 127,095 shares ICS Opportunities II LLC holdings: 126,828 shares Other trading entities holdings: 267 shares

3 metrics

Indirect Common Stock holdings 127,095 shares Total shares indirectly owned following the reported holding entry

ICS Opportunities II LLC holdings 126,828 shares Common Stock held by ICS Opportunities II LLC

Other trading entities holdings 267 shares Common Stock held by other trading entities under Millennium’s control

Key Terms

voting control, investment discretion, beneficial ownership, pecuniary interest, +1 more

5 terms

voting control financial

"subject to voting control and investment discretion by Millennium Management LLC"

investment discretion financial

"subject to voting control and investment discretion by Millennium Management LLC"

beneficial ownership financial

"Each reporting person disclaims beneficial ownership of the shares of the Company's Common Stock disclosed herein"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"except to the extent of such reporting person's pecuniary interest therein, if any"

ten percent owner financial

"reporting persons are indicated as ten percent owners in the filing metadata"

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Accepted by SEC EDGAR 05/15/2026 - 04:21 PM Learn about SEC filing dates

FAQ

What does the Form 3 for Sensei Biotherapeutics (SNSE) disclose?

The Form 3 discloses initial beneficial ownership of 127,095 Common Stock shares in Sensei Biotherapeutics, Inc. held indirectly through Millennium-affiliated entities, establishing them as significant shareholders and ten percent owners under SEC reporting rules.

Who holds Sensei Biotherapeutics (SNSE) shares in this Form 3 filing?

Shares are held by ICS Opportunities II LLC and other trading entities subject to voting control and investment discretion of Millennium Management LLC, Millennium Group Management LLC, and Israel A. Englander, according to the disclosure language in the filing’s footnotes.

How many SNSE shares does ICS Opportunities II LLC hold?

ICS Opportunities II LLC holds 126,828 shares of Sensei Biotherapeutics Common Stock. Additional trading entities under Millennium Management LLC’s control hold a further 267 shares, bringing total reported indirect holdings in the filing to 127,095 shares.

Do Millennium-related reporting persons claim full beneficial ownership of SNSE shares?

No. Each reporting person disclaims beneficial ownership of the Sensei Biotherapeutics Common Stock disclosed, except to the extent of their pecuniary interest, meaning economic exposure rather than full ownership of all reported shares.

Why are Millennium entities listed as ten percent owners of SNSE?

They are listed as ten percent owners because their aggregate indirect holdings and control meet SEC thresholds requiring beneficial ownership reporting, even though they disclaim beneficial ownership beyond any pecuniary interest in the reported Common Stock positions.

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

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

MILLENNIUM MANAGEMENT LLC

(Last) (First) (Middle)

399 PARK AVENUE

(Street)

NEW YORK NEW YORK 10022

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
03/26/2026

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

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

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

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

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	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	127,095	I	See Footnote(1)(2)

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

1. Name and Address of Reporting Person^*

MILLENNIUM MANAGEMENT LLC

(Last) (First) (Middle)

399 PARK AVENUE

(Street)

NEW YORK NEW YORK 10022

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

ICS OPPORTUNITIES II LLC

(Last) (First) (Middle)

C/O MILLENNIUM MANAGEMENT LLC

399 PARK AVENUE

(Street)

NEW YORK NEW YORK 10022

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

MILLENNIUM GROUP MANAGEMENT LLC

(Last) (First) (Middle)

399 PARK AVENUE

(Street)

NEW YORK NEW YORK 10022

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

ENGLANDER ISRAEL A

(Last) (First) (Middle)

C/O MILLENNIUM MANAGEMENT LLC

399 PARK AVENUE

(Street)

NEW YORK NEW YORK 10022

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. The shares of Sensei Biotherapeutics, Inc. (the "Company") common stock ("Common Stock"), par value $0.0001 per share, disclosed herein were held 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).

2. ICS Opportunities II LLC held 126,828 shares of the Company's Common Stock. Other trading entities subject to voting control and investment discretion by Millennium Management LLC held an aggregate of 267 shares of the Company's Common Stock. 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.

	MILLENNIUM MANAGEMENT LLC: By: /s/ Gil Raviv, Global General Counsel	05/14/2026
	ICS OPPORTUNITIES II LLC, By: Millennium Management LLC, its Investment Manager: By: /s/ Gil Raviv, Global General Counsel	05/14/2026
	MILLENNIUM GROUP MANAGEMENT LLC: By: /s/ Gil Raviv, Global General Counsel	05/14/2026
	/s/ Israel A. Englander	05/14/2026
	** 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.
* Form 3: SEC 1473 (03-26)