Cabaletta Bio (CABA) CEO Steven Nichtberger purchases 45,000 shares

Rhea-AI Filing Summary

Cabaletta Bio, Inc. President & CEO Steven Nichtberger reported buying 45,000 shares of the company’s common stock on January 21, 2026 at a weighted average price of $2.2395 per share. The filing notes these shares were purchased in multiple trades at prices ranging from $2.1985 to $2.26. Following this direct purchase, he beneficially owned 1,031,483 shares held directly.

The Form 4 also shows an additional 363,000 shares reported as indirectly held by the 2017 Nichtberger Family Trust, for which he disclaims beneficial ownership. The price detail and range are available on request from the issuer or the SEC staff, as stated in the footnote.

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

OMB APPROVAL

OMB Number:			3235-0287
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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^*

Nichtberger Steven

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
01/21/2026

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
Common Stock	01/21/2026		P		45,000	A	$2.2395(1)	1,031,483	D
Common Stock								363,000	I	By 2017 Nichtberger Family Trust(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

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These shares were purchased at prices ranging from $2.1985 to $2.26, 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.

2. The reporting person disclaims beneficial ownership of these securities, and the filing of this report is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

	By: /s/ Michael Gerard, as Attorney-in-Fact	01/21/2026
	** 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 4 (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.

FAQ

What insider transaction did Cabaletta Bio (CABA) report for Steven Nichtberger?

Steven Nichtberger, President & CEO and a director of Cabaletta Bio, Inc. (CABA), reported purchasing 45,000 shares of common stock on January 21, 2026 in an open-market transaction.

At what price did the Cabaletta Bio CEO buy the 45,000 CABA shares?

The 45,000 Cabaletta Bio shares were bought at a weighted average price of $2.2395 per share, with individual trades executed between $2.1985 and $2.26, inclusive.

How many Cabaletta Bio shares does Steven Nichtberger own after this transaction?

After the reported purchase, Steven Nichtberger beneficially owned 1,031,483 shares of Cabaletta Bio common stock directly, according to the Form 4.

What is the 2017 Nichtberger Family Trust’s reported Cabaletta Bio holding?

The Form 4 lists 363,000 Cabaletta Bio common shares as indirectly held “By 2017 Nichtberger Family Trust.” A footnote states that the reporting person disclaims beneficial ownership of these securities.

What does the weighted average price disclosure mean in this Cabaletta Bio Form 4?

The filing explains that the $2.2395 figure is a weighted average price across multiple trades between $2.1985 and $2.26. The reporting person has offered to provide full trade-by-trade price details to the issuer, security holders, or SEC staff upon request.

What roles does Steven Nichtberger hold at Cabaletta Bio (CABA)?

Steven Nichtberger is identified in the Form 4 as both a Director and an Officer of Cabaletta Bio, Inc., serving as President & CEO.