Cabaletta Bio (CABA) grants 175,000 stock options to General Counsel

Rhea-AI Filing Summary

Cabaletta Bio, Inc. reported that its General Counsel, Gerard Michael, received a grant of stock options covering 175,000 shares of common stock. The options were awarded at an exercise price of $0.00 per share, reflecting a compensatory equity award rather than an open-market purchase.

According to the vesting terms, 25% of the shares subject to the option will vest and become exercisable on March 1, 2027. The remaining 75% will vest in twelve substantially equal quarterly installments after that date, conditioned on his continued service with the company on each vesting date.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Gerard Michael

(Last) (First) (Middle)

C/O CABALETTA BIO, INC.

2929 ARCH STREET, SUITE 600

(Street)

PHILADELPHIA PA 19104

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cabaletta Bio, Inc. [ CABA ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
03/02/2026

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

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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$3.3	03/02/2026		A		175,000		(1)	03/01/2036	Common Stock	175,000	$0.00	175,000	D

Explanation of Responses:

1. 25% of the shares underlying this option shall vest and become exercisable on March 1, 2027, with the remainder vesting in twelve substantially equal quarterly installments thereafter, subject to the reporting person's continued service on each such vesting date.

	By: /s/ Michael Gerard, as Attorney-in-Fact	03/02/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Cabaletta Bio (CABA) disclose for Gerard Michael?

Cabaletta Bio disclosed that General Counsel Gerard Michael was granted stock options for 175,000 shares of common stock. The award is a compensatory option grant rather than a market purchase, reflected at an exercise price of $0.00 per share in the filing.

How many Cabaletta Bio (CABA) shares are covered by the new option grant?

The option grant to Cabaletta Bio’s General Counsel covers 175,000 shares of common stock. This entire amount was reported as held following the transaction, indicating it is a new equity award rather than a partial modification or incremental adjustment to an existing grant.

What is the vesting schedule for Gerard Michael’s Cabaletta Bio (CABA) stock options?

The filing states that 25% of the option shares vest on March 1, 2027. The remaining shares vest in twelve substantially equal quarterly installments thereafter, and each vesting installment depends on his continued service with the company on the relevant vesting date.

Is the Cabaletta Bio (CABA) option grant to Gerard Michael an acquisition, sale, or other type of transaction?

The transaction is classified as an acquisition through a grant or award of derivative securities. It is coded as a stock option grant, not an open-market buy or sell, and reflects equity-based compensation for the General Counsel’s role at the company.

What role does Gerard Michael hold at Cabaletta Bio (CABA) in this insider filing?

In this insider report, Gerard Michael is identified as an officer of Cabaletta Bio serving as General Counsel. The reported transaction relates to a stock option compensation award associated with his executive position rather than trading activity by a non-employee director or outside shareholder.

Are there any special conditions tied to the Cabaletta Bio (CABA) option grant for Gerard Michael?

Yes. Vesting is explicitly subject to continued service on each vesting date. If Gerard Michael does not remain in service through a vesting date, the unvested portion may not become exercisable, reflecting standard retention-focused conditions for executive equity compensation awards.