RA Capital funds receive Climb Bio (CLYM) pre-funded warrants in new grant

Rhea-AI Filing Summary

Climb Bio, Inc. reported that investment entities affiliated with RA Capital acquired pre-funded warrants linked to its common stock. The filing shows an indirect grant of 2,106,000 Pre-Funded Warrants, each exercisable for one share of common stock.

The warrants were acquired at $9.4999 per warrant and have a nominal exercise price of $0.0001 per share. They are exercisable immediately and have no expiration date, but their exercise is limited so that RA Capital–affiliated holders and related groups cannot beneficially own more than 33.0% of Climb Bio’s outstanding common stock after exercise. Following this grant, the reporting RA Capital entities show 22,546,000 pre-funded warrants beneficially owned, subject to footnoted pecuniary-interest and beneficial-ownership disclaimers.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider RA CAPITAL MANAGEMENT, L.P., RA Capital Healthcare Fund LP, RA Capital Nexus Fund, L.P., RA Capital Nexus Fund II, L.P., RA Capital Nexus Fund III, L.P., Kolchinsky Peter, Shah Rajeev M.

Role null | null | null | null | null | null | null

Type	Security	Shares	Price	Value
Grant/Award	Pre-Funded Warrants (Right to Buy)	2,106,000	$9.4999	$20.01M

Holdings After Transaction: Pre-Funded Warrants (Right to Buy) — 22,546,000 shares (Indirect, See footnotes)

Footnotes (1)

1. The Pre-Funded Warrants have no expiration date and are exercisable immediately. Notwithstanding the foregoing, the Reporting Persons shall not be entitled to exercise the Pre-Funded Warrant if it would cause the aggregate number of shares of Common Stock beneficially owned by the Reporting Persons, their affiliates and any persons who are members of a Section 13(d) group with the Reporting Persons or their affiliates to exceed 33.0% of the total number of issued and outstanding shares of Common Stock of the Issuer following such exercise. These securities are held directly by RA Capital Healthcare Fund, L.P. (the "Fund"). RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus II Fund, L.P. (the "Nexus Fund II"), RA Capital Nexus III Fund, L.P. (the "Nexus Fund III") and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Fund and the Nexus Fund III collectively own approximately 75% of the outstanding equity interests of Sera Medicines, LLC ("Sera"). Accordingly, each of the Fund, the Nexus Fund III and the Adviser may be deemed to beneficially own the securities held by Sera. The Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund II, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of the reported securities, except to the extent of their respective pecuniary interest therein.

Key Figures

Pre-Funded Warrants granted: 2,106,000 warrants Price per warrant: $9.4999 per warrant Exercise price: $0.0001 per share +2 more

5 metrics

Pre-Funded Warrants granted 2,106,000 warrants Grant/award acquisition reported on Form 4

Price per warrant $9.4999 per warrant Acquisition price for new pre-funded warrants

Exercise price $0.0001 per share Nominal exercise price of pre-funded warrants

Ownership cap 33.0% of common stock Maximum beneficial ownership allowed after exercise

Warrants after transaction 22,546,000 warrants Total pre-funded warrants beneficially owned after grant

Key Terms

Pre-Funded Warrants, beneficially owned, Section 13(d) group, pecuniary interest, +1 more

5 terms

Pre-Funded Warrants financial

"The Pre-Funded Warrants have no expiration date and are exercisable immediately."

Pre-funded warrants are financial instruments that give investors the right to purchase a company's stock at a set price, but with most or all of the purchase price paid upfront. They function like a coupon or gift card for stock, allowing investors to buy shares later at a fixed price, which can be beneficial if they want to avoid future price increases. This makes them important for investors seeking flexibility and certainty in their investment plans.

beneficially owned financial

"shares of Common Stock beneficially owned by the Reporting Persons, their affiliates"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Section 13(d) group regulatory

"any persons who are members of a Section 13(d) group with the Reporting Persons"

pecuniary interest financial

"disclaim beneficial ownership of the reported securities, except to the extent of their respective pecuniary interest therein."

separately managed account financial

"and a separately managed account (the "Account")."

A separately managed account (SMA) is a personalized investment portfolio owned by a single investor and run by a professional manager who buys and sells securities on that investor’s behalf. It matters to investors because an SMA offers tailored asset selection, tax handling, and transparency—like hiring a personal chef who prepares meals to your dietary needs rather than sharing a set menu—so you can align holdings with your goals and see exactly what you own.

Form 4 Insider Transactions: What Each Field Means →

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
Estimated average burden
hours per response:			0.5

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^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Climb Bio, Inc. [ CLYM ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/29/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

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

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

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
Pre-Funded Warrants (Right to Buy)	$0.0001	04/29/2026		A		2,106,000		(1)	(1)	Common Stock	2,106,000	$9.4999	22,546,000	I	See footnotes(2)(3)

1. Name and Address of Reporting Person^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

RA Capital Healthcare Fund LP

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

RA Capital Nexus Fund, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

RA Capital Nexus Fund II, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

RA Capital Nexus Fund III, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Kolchinsky Peter

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Shah Rajeev M.

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. The Pre-Funded Warrants have no expiration date and are exercisable immediately. Notwithstanding the foregoing, the Reporting Persons shall not be entitled to exercise the Pre-Funded Warrant if it would cause the aggregate number of shares of Common Stock beneficially owned by the Reporting Persons, their affiliates and any persons who are members of a Section 13(d) group with the Reporting Persons or their affiliates to exceed 33.0% of the total number of issued and outstanding shares of Common Stock of the Issuer following such exercise.

2. These securities are held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

3. RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus II Fund, L.P. (the "Nexus Fund II"), RA Capital Nexus III Fund, L.P. (the "Nexus Fund III") and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Fund and the Nexus Fund III collectively own approximately 75% of the outstanding equity interests of Sera Medicines, LLC ("Sera"). Accordingly, each of the Fund, the Nexus Fund III and the Adviser may be deemed to beneficially own the securities held by Sera. The Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund II, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of the reported securities, except to the extent of their respective pecuniary interest therein.

Remarks:

Dr. Andrew Levin, a Partner and Managing Director of the Adviser, serves on the Issuer's board of directors.

	/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.	04/29/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P.	04/29/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC, the General Partner of RA Capital Nexus Fund, L.P.	04/29/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC, the General Partner of RA Capital Nexus Fund II, L.P.	04/29/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P.	04/29/2026
	/s/ Peter Kolchinsky, individually	04/29/2026
	/s/ Rajeev Shah, individually	04/29/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did RA Capital report for Climb Bio (CLYM)?

RA Capital–affiliated entities reported receiving 2,106,000 Pre-Funded Warrants linked to Climb Bio common stock. The filing characterizes this as a grant or award acquisition rather than an open-market purchase, increasing their derivative exposure to the company.

What are the key terms of Climb Bio’s pre-funded warrants held by RA Capital?

The pre-funded warrants are exercisable immediately, have no expiration date, and carry a nominal exercise price of $0.0001 per share. Each warrant is linked to one share of Climb Bio common stock, providing long-duration exposure with minimal exercise cost.

How much did RA Capital pay for the new Climb Bio pre-funded warrants?

RA Capital–affiliated entities acquired the new pre-funded warrants at $9.4999 per warrant. With 2,106,000 warrants granted, this reflects a substantial notional investment in Climb Bio via derivative securities rather than direct common share purchases.

Is there a cap on RA Capital’s ownership from Climb Bio’s pre-funded warrants?

Yes. The warrants cannot be exercised if doing so would cause RA Capital, its affiliates, and related Section 13(d) group members to beneficially own more than 33.0% of Climb Bio’s outstanding common stock after exercise, effectively limiting maximum ownership concentration.

How many Climb Bio pre-funded warrants do RA Capital entities report after this grant?

After the grant, RA Capital–affiliated reporting persons show beneficial ownership of 22,546,000 Pre-Funded Warrants. Footnotes explain these are held through RA Capital Healthcare Fund, L.P. and related entities, with certain parties disclaiming beneficial ownership beyond pecuniary interests.