SEC FORM 3

SEC FORM 3 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

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1. Name and Address of Reporting Person^*

Das Arun

(Last)

(First)

(Middle)

CABALETTA BIO, INC.

2929 ARCH STREET, SUITE 600

(Street)

PHILADELPHIA

19104

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
01/05/2022

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

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

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

5. 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 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)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	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)
Stock Option (Right to Buy)	⁽¹⁾	11/15/2028	Common Stock	29,168	1.01	D
Stock Option (Right to Buy)	⁽²⁾	10/23/2029	Common Stock	18,416	11	D
Stock Option (Right to Buy)	⁽³⁾	02/28/2031	Common Stock	35,000	11.47	D

Explanation of Responses:

1. 21,529 shares underlying this option have vested and the remainder shall vest in substantially equal monthly installments from January 16, 2022 to November 16, 2022, subject to the reporting person's continued service on each such vesting date.

2. 25% of the shares underlying this option vested and became exercisable on October 24, 2020, with the remainder vesting in twelve substantially equal quarterly installments thereafter, subject to the reporting person's continued service on each such vesting date.

3. 25% of the shares underlying this option shall vest and become exercisable on March 1, 2022, with the remainder vesting in twelve substantially equal quarterly installments thereafter, subject to the reporting person's continued service on each such vesting date.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Arun Das	01/13/2022
	** 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.

SEC Form 3 filed by new insider Das Arun