Cormorant Asset Management (CABA) discloses 10M-share Cabaletta Bio stake

Rhea-AI Filing Summary

Cormorant Asset Management, LP and Bihua Chen report a 5.95% beneficial stake in Cabaletta Bio, Inc. The filing covers common stock, including shares issuable from warrants. They beneficially own 10,000,000 shares of common stock, based on Cabaletta Bio’s reported 163,054,796 shares outstanding as of May 7, 2026.

The 10,000,000-share position consists of 5,000,000 common shares and warrants to purchase an additional 5,000,000 shares. Both Cormorant Asset Management and Bihua Chen report shared voting and dispositive power over all 10,000,000 shares, with no sole voting or dispositive power. The economic rights to dividends and sale proceeds reside with the Cormorant Funds, including Cormorant Global Healthcare Master Fund, LP, which may receive dividends or proceeds relating to more than 5% of the class.

Key Figures

Beneficial ownership: 10,000,000 shares Percent of class: 5.95% Shares currently held: 5,000,000 shares +4 more

7 metrics

Beneficial ownership 10,000,000 shares Total Cabaletta Bio common shares beneficially owned by the reporting persons

Percent of class 5.95% Portion of Cabaletta Bio common stock represented by 10,000,000 shares

Shares currently held 5,000,000 shares Common stock of Cabaletta Bio directly held by the Cormorant Funds

Warrants held 5,000,000 shares Shares of Cabaletta Bio common stock issuable upon exercise of warrants

Shares outstanding baseline 163,054,796 shares Cabaletta Bio common shares outstanding as of May 7, 2026, used for ownership percentage

Shared voting power 10,000,000 shares Shares over which the reporting persons share power to vote or direct the vote

Shared dispositive power 10,000,000 shares Shares over which the reporting persons share power to dispose or direct disposition

Key Terms

beneficial owner, shared voting power, dispositive power, warrants, +1 more

5 terms

beneficial owner financial

"beneficial owner of the shares reported herein"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

shared voting power financial

"Shared Voting Power 10,000,000.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

dispositive power financial

"Shared Dispositive Power 10,000,000.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

warrants financial

"shares of Common Stock issuable upon the exercise of warrants"

Warrants are special documents that give you the right to buy a company's stock at a set price before a certain date. They are often used as a way for companies to attract investors or raise money, and their value can increase if the company's stock price goes up.

percent of class financial

"Percent of class: 5.95%"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

FAQ

What percentage of Cabaletta Bio (CABA) does Cormorant Asset Management report owning?

Cormorant Asset Management and Bihua Chen report beneficial ownership of 5.95% of Cabaletta Bio’s common stock. This percentage is calculated against 163,054,796 shares outstanding as of May 7, 2026, as disclosed in Cabaletta Bio’s Form 10-Q.

How many Cabaletta Bio (CABA) shares are reported as beneficially owned by Cormorant?

The reporting persons disclose beneficial ownership of 10,000,000 Cabaletta Bio common shares. This includes 5,000,000 currently held shares and warrants to purchase an additional 5,000,000 shares of common stock.

What role do warrants play in Cormorant’s Cabaletta Bio (CABA) position?

Cormorant’s reported position includes warrants to purchase 5,000,000 shares of Cabaletta Bio common stock. Combined with 5,000,000 existing shares, these warrants bring the total reported beneficial ownership to 10,000,000 shares.

Who has voting and dispositive power over Cabaletta Bio (CABA) shares held by Cormorant?

Cormorant Asset Management and Bihua Chen report shared voting power and shared dispositive power over 10,000,000 shares. They report no sole voting or sole dispositive power over Cabaletta Bio common stock.

Which Cormorant fund holds more than 5% of Cabaletta Bio (CABA)?

The filing states that Cormorant Global Healthcare Master Fund, LP, a Cormorant Fund, has the right to receive or direct dividends or sale proceeds relating to more than 5% of Cabaletta Bio’s common stock.

On whose behalf is the Cabaletta Bio (CABA) stake reported in this ownership filing?

The stake is reported by Cormorant Asset Management, LP, as investment adviser to certain Cormorant Funds, and by Bihua Chen. The filing clarifies that economic rights belong to the Cormorant Funds, including Cormorant Global Healthcare Master Fund, LP.

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Available on EDGAR 08/14/2026 - 02:01 PM Accepted by SEC EDGAR 08/14/2026 - 02:01 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 4)

Cabaletta Bio, Inc.

(Name of Issuer)

Common Stock, par value $0.00001 per share

(Title of Class of Securities)

12674W109

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 12674W109

1

Names of Reporting Persons

Cormorant Asset Management, LP

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 10,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 10,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,000,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.95 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP Number(s): 12674W109

1

Names of Reporting Persons

Bihua Chen

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 10,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 10,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,000,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.95 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Cabaletta Bio, Inc.
(b)	Address of issuer's principal executive offices: 2929 Arch Street, Suite 600, Philadelphia, PA 19104
Item 2.
(a)	Name of person filing: Cormorant Asset Management, LP Bihua Chen This statement is filed by (i) Cormorant Asset Management, LP, a Delaware limited partnership, and the investment adviser to certain funds (the "Cormorant Funds"), with respect to the shares directly held by the Cormorant Funds and (ii) Bihua Chen with respect to the shares directly held by the Cormorant Funds. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." The filing of this statement should not be construed as an admission that any of the foregoing persons or any Reporting Person is, for the purposes of Section 13 of the Act, the beneficial owner of the shares reported herein.
(b)	Address or principal business office or, if none, residence: 200 Clarendon Street, 50th Floor Boston, MA 02116
(c)	Citizenship: Cormorant Asset Management, LP - Delaware Bihua Chen - United States
(d)	Title of class of securities: Common Stock, par value $0.00001 per share
(e)	CUSIP No.: 12674W109
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 10,000,000
(b)	Percent of class: 5.95%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 10,000,000
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 10,000,000 The Reporting Persons' holdings reported herein reflect shares of common stock of the Issuer ("Common Stock") issuable upon the exercise of warrants (the "Warrants"). The Reporting Persons are the beneficial owners of 5,000,000 shares of Common Stock and hold Warrants to purchase 5,000,000 shares of Common Stock. The percentages reported herein with respect to the Reporting Persons' holdings are calculated based upon a statement in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2026, as filed with the Securities and Exchange Commission on May 14, 2026, that there were 163,054,796 shares of Common Stock of the Issuer outstanding as of May 7, 2026.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. See Item 2. The Cormorant Funds have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the shares reported herein. Cormorant Global Healthcare Master Fund, LP, a Cormorant Fund, has the right to receive or the power to direct the receipt of dividends or the proceeds from the sale of more than 5% of the shares.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Cormorant Asset Management, LP

Signature:	/s/ Bihua Chen
Name/Title:	Bihua Chen, Managing Member
Date:	08/14/2026

Bihua Chen

Signature:	/s/ Bihua Chen
Name/Title:	Bihua Chen
Date:	08/14/2026

Exhibit Information

Joint Filing Statement, incorporated by reference to the Joint Filing Statement included with the Schedule 13G filed by the Reporting Persons on August 14, 2025.