5AM Opportunities I Form 4 Cabaletta Bio / SCOTT M ROCKLAGE ownership change

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).

1. Name and Address of Reporting Person^*

5AM Ventures V, L.P.

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

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

3. Date of Earliest Transaction (Month/Day/Year)
09/07/2021

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

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 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
Common Stock	09/07/2021		S		625,000	D	$9.7	1,989,575	I	See footnotes(1)
Common Stock								369,688	I	See footnotes(2)

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

1. Name and Address of Reporting Person^*

5AM Ventures V, L.P.

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

5AM Opportunities I (GP), LLC

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

5AM Opportunities I, L.P.

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

5AM Partners V, LLC

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

PARMAR KUSH

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

ROCKLAGE SCOTT M

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Schwab Andrew J.

(Last) (First) (Middle)

501 2ND STREET, SUITE 350

(Street)

SAN FRANCISCO CA 94107

(City) (State) (Zip)

Explanation of Responses:

1. Shares are held by 5AM Ventures V, L.P. ("5AM V"). 5AM Partners V, LLC ("5AM Partners") is the sole general partner of 5AM V. Dr. Kush Parmar, Andrew J. Schwab and Dr. Scott M. Rocklage are managing members of 5AM Partners and may be deemed to have shared voting and investment power over the shares beneficially owned by 5AM V. Each of 5AM Partners, Dr. Parmar, Mr. Schwab and Dr. Rocklage disclaims beneficial ownership of the shares of Common Stock held by 5AM V, except to the extent of its or his pecuniary interest therein.

2. Shares are held by 5AM Opportunities I, L.P. ("Opportunities"). 5AM Opportunities I (GP), LLC ("Opportunities GP") is the sole general partner of Opportunities. Andrew J. Schwab and Dr. Kush Parmar are managing members of Opportunities GP and may be deemed to have shared voting and investment power over the shares beneficially owned by Opportunities. Each of Opportunities GP, Mr. Schwab and Dr. Parmar disclaims beneficial ownership of the shares of Common Stock held by Opportunities, except to the extent of its or his pecuniary interest therein.

Remarks:

	5AM Ventures V, L.P., By: 5AM Partners V, LLC, its General Partner, By /s/ Scott M. Rocklage, Managing Member	09/09/2021
	5AM Opportunities I (GP), LLC, By /s/ Kush Parmar, Managing Member	09/09/2021
	5AM Opportunities I, L.P., By: 5AM Opportunities I (GP), LLC, its General Partner, By /s/ Kush Parmar, Managing Member	09/09/2021
	5AM Partners V, LLC, By /s/ Scott M. Rocklage, Managing Member	09/09/2021
	/s/ Kush Parmar	09/09/2021
	/s/ Scott Rocklage	09/09/2021
	/s/ Andrew J. Schwab	09/09/2021
	** Signature of Reporting Person	Date
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