Mark Simon - 21 Jan 2026 Form 4 Insider Report for Cabaletta Bio, Inc. (CABA)

Role: Director
Signature: By: /s/ Michael Gerard, as Attorney-in-Fact
Issuer symbol: CABA
Transactions as of: 21 Jan 2026
Net transactions value: +$25,261
Form type: 4
Filing time: 21 Jan 2026, 18:53:57 UTC
Previous filing: 09 Jun 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Simon Mark	Director	C/O CABALETTA BIO, INC., 2929 ARCH STREET, SUITE 600, PHILADELPHIA	By: /s/ Michael Gerard, as Attorney-in-Fact	21 Jan 2026	0001400717

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CABA	Common Stock	Purchase	$25,261	+11,061	+8.1%	$2.28	147,205	21 Jan 2026	Direct	F1
holding	CABA	Common Stock						7,000	21 Jan 2026	By Spouse

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The price reported in Column 4 is a weighted average price. These shares were purchased at prices ranging from $2.245 to $2.32, inclusive. The reporting person has provided to the Issuer, and undertakes to provide any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.

Content

The price reported in Column 4 is a weighted average price. These shares were purchased at prices ranging from $2.245 to $2.32, inclusive. The reporting person has provided to the Issuer, and undertakes to provide any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.