Sensei director reports Series B preferred holdings

Sensei Biotherapeutics, Inc. director Stephen M. Hahn filed an initial ownership report on Form 3.

Rhea-AI Filing Summary

Sensei Biotherapeutics, Inc. director Stephen M. Hahn filed an initial ownership report on Form 3. The filing shows his beneficial ownership of Series B Preferred Stock, which is a convertible security linked to the company’s common stock.

Each share of Series B Preferred Stock is convertible into 1,000 shares of common stock and has no expiration date, giving long-term equity exposure rather than a short-term trading position. The filing notes that this preferred stock position arose in connection with a completed merger involving Faeth Holdings Therapeutics, Inc. and related entities, where HoldCo common stock was converted into the right to receive shares of Sensei’s Series B Preferred Stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Hahn Stephen M.

Role Director

Type	Security	Shares	Price	Value
holding	Series B Preferred Stock	--	--	--

Holdings After Transaction: Series B Preferred Stock — 44,763 contracts (Direct)

Footnotes (3)

1. F1. Subject to certain conditions set forth in the Certificate of Designation of Preferences, Rights and Limitations of the Series B Preferred Stock, each share of Series B Preferred Stock is convertible into 1,000 shares of the Issuer's Common Stock and has no expiration date.
2. F2. Pursuant to February 17, 2026 Agreement and Plan of Merger (the "Merger Agreement"), by and among the Issuer, Sapphire First Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Issuer ("First Merger Sub"), Sapphire Second Merger Sub, LLC, a Delaware limited liability company and wholly owned subsidiary of the Issuer ("Second Merger Sub"), Faeth Holdings Therapeutics, Inc. ("HoldCo") and Faeth Therapeutics, LLC, a Delaware limited liability company and wholly owned subsidiary of HoldCo ("Faeth"), First Merger Sub merged with and into HoldCo, with HoldCo surviving the first merger as a wholly owned subsidiary of the Issuer, and immediately following the first merger, HoldCo merged with and into Second Merger Sub, with Second Merger Sub surviving the second merger as a wholly owned subsidiary of the Issuer (such mergers, the "Merger").
3. F3. Footnote continued: Upon the closing of the Merger, shares of outstanding common stock of HoldCo were converted into the right to receive 44.763 shares of the Issuer's Series B Preferred Stock.

Key Figures

Conversion ratio: 1,000 shares of common stock per preferred share Exercise price: $0.0000 per share Expiration: No expiration date

3 metrics

Conversion ratio 1,000 shares of common stock per preferred share Series B Preferred Stock conversion feature

Exercise price $0.0000 per share Conversion/exercise price of Series B Preferred Stock

Expiration No expiration date Series B Preferred Stock has no stated expiration

Key Terms

Series B Preferred Stock, Certificate of Designation of Preferences, Rights and Limitations, Agreement and Plan of Merger, Merger, +1 more

5 terms

Series B Preferred Stock financial

"each share of Series B Preferred Stock is convertible into 1,000 shares"

Series B preferred stock is a type of ownership share issued by a company that offers certain advantages over common stock, such as priority in receiving dividends or assets if the company is sold or liquidated. It is typically issued after an initial round of funding, making it a way for investors to support a company's growth while gaining some protections and benefits. This stock matters to investors because it often provides a more secure investment position with potential for future growth.

Certificate of Designation of Preferences, Rights and Limitations regulatory

"Subject to certain conditions set forth in the Certificate of Designation of Preferences, Rights and Limitations"

Agreement and Plan of Merger regulatory

"Pursuant to February 17, 2026 Agreement and Plan of Merger"

An Agreement and Plan of Merger is a formal document where two companies agree to combine into one, outlining how the process will happen. It’s like a step-by-step plan for merging, and it matters because it shows both sides have agreed on the details before the official transition takes place.

Merger financial

"such mergers, the "Merger""

A merger is when two companies combine into a single business, with ownership and control reorganized so they operate as one entity. For investors it matters because mergers can change the value and risk of holdings—shares may be exchanged, diluted, or rise if the combined company saves costs or gains market power, and the deal often depends on regulatory approval and successful integration like two households joining resources and routines.

underlying security financial

"underlying security title: Common Stock"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does Stephen M. Hahn’s Form 3 for SNSE disclose?

The Form 3 discloses Stephen M. Hahn’s beneficial ownership of Series B Preferred Stock of Sensei Biotherapeutics. This preferred stock is convertible into common shares and reflects his equity position following a merger transaction involving Faeth Holdings Therapeutics and related entities.

How is Sensei Biotherapeutics’ Series B Preferred Stock structured?

Each share of Series B Preferred Stock is convertible into 1,000 shares of common stock and has no expiration date. This structure provides long-term conversion rights rather than a short-term option, aligning the holder with future common equity performance.

How did Stephen M. Hahn receive Sensei Biotherapeutics’ Series B Preferred Stock?

Hahn’s Series B Preferred Stock position arose upon closing of a merger involving Sensei Biotherapeutics, Faeth Holdings Therapeutics, and related entities. Outstanding HoldCo common shares were converted into the right to receive shares of Sensei’s Series B Preferred Stock as merger consideration.

Does the Series B Preferred Stock reported by Hahn have an expiration date?

According to the filing’s footnotes, each share of Series B Preferred Stock has no expiration date. Combined with its 1,000-to-1 conversion feature into common stock, this creates a perpetual convertible equity interest in Sensei Biotherapeutics.

What underlying security is linked to the Series B Preferred Stock in Hahn’s Form 3?

The Series B Preferred Stock is convertible into common stock of Sensei Biotherapeutics. The filing specifies that each preferred share can be converted into 1,000 common shares, making the common stock the underlying security for this preferred position.

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Accepted by SEC EDGAR 06/16/2026 - 04:18 PM EDT Learn about SEC filing dates

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^*

Hahn Stephen M.

(Last) (First) (Middle)

C/O FAETH THERAPEUTICS, INC.

701 TILLERY STREET #12 #1010

(Street)

AUSTIN TEXAS 78702

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
06/12/2026

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

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)

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

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)

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
Series B Preferred Stock(1)	(2)(3)	(2)(3)	Common Stock	44,763(2)(3)	(2)(3)	D

Explanation of Responses:

1. Subject to certain conditions set forth in the Certificate of Designation of Preferences, Rights and Limitations of the Series B Preferred Stock, each share of Series B Preferred Stock is convertible into 1,000 shares of the Issuer's Common Stock and has no expiration date.

2. Pursuant to February 17, 2026 Agreement and Plan of Merger (the "Merger Agreement"), by and among the Issuer, Sapphire First Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Issuer ("First Merger Sub"), Sapphire Second Merger Sub, LLC, a Delaware limited liability company and wholly owned subsidiary of the Issuer ("Second Merger Sub"), Faeth Holdings Therapeutics, Inc. ("HoldCo") and Faeth Therapeutics, LLC, a Delaware limited liability company and wholly owned subsidiary of HoldCo ("Faeth"), First Merger Sub merged with and into HoldCo, with HoldCo surviving the first merger as a wholly owned subsidiary of the Issuer, and immediately following the first merger, HoldCo merged with and into Second Merger Sub, with Second Merger Sub surviving the second merger as a wholly owned subsidiary of the Issuer (such mergers, the "Merger").

3. Footnote continued: Upon the closing of the Merger, shares of outstanding common stock of HoldCo were converted into the right to receive 44.763 shares of the Issuer's Series B Preferred Stock.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Josiah Craver, Attorney-in-Fact	06/16/2026
	** 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)