Climb Bio director sells 100K shares at $13.67

Climb Bio, Inc. (CLYM) director Thomas Stephen Basil reported selling 100,000 shares of common stock on September 15, 2026 at a weighted average price of $13.6682 per share, in transactions executed under a Rule 10b5-1 trading plan adopted on June 16, 2026.

Rhea-AI Filing Summary

Climb Bio, Inc. (CLYM) director Thomas Stephen Basil reported selling 100,000 shares of common stock on September 15, 2026 at a weighted average price of $13.6682 per share, in transactions executed under a Rule 10b5-1 trading plan adopted on June 16, 2026. After these sales, he reported owning 467,969 shares directly, which include 413,312 shares received for no consideration in a pro-rata in-kind distribution from Sera Medicines, LLC.

Insider Trade Summary 10b5-1

Net Seller: 100,000 shares

Net Sell 1 txn

Insider Thomas Stephen Basil

Role Director

Sold 100,000 shs ($1.37M)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2, F3	100,000	$13.6682	$1.37M

Holdings After Transaction: Common Stock — 467,969 shares (Direct)

Footnotes (3)

1. F1. These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 16, 2026.
2. F2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.3800 to $14.3400, inclusive. The reporting person undertakes to provide the staff of the Securities and Exchange Commission, the issuer or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price within the range.
3. F3. Includes 413,312 shares of the issuer's common stock, par value $0.0001 per share, distributed by Sera Medicines, LLC to certain of its limited partners, including the reporting person, for no consideration in a pro-rata in-kind distribution.

Key Figures

Shares sold: 100,000 shares Weighted average sale price: $13.6682 per share Sale price range: $13.38 to $14.34 per share +3 more

6 metrics

Shares sold 100,000 shares Common stock sold on September 15, 2026

Weighted average sale price $13.6682 per share Average price across multiple sale transactions on September 15, 2026

Sale price range $13.38 to $14.34 per share Range of individual trade prices for the 100,000 shares sold

Shares held after transaction 467,969 shares Direct holdings of Thomas Stephen Basil after the September 15, 2026 sale

In-kind distribution shares 413,312 shares Shares received for no consideration from Sera Medicines, LLC, included in post-sale holdings

Rule 10b5-1 plan adoption date June 16, 2026 Date the trading plan governing these sales was adopted

Key Terms

Rule 10b5-1 trading plan, weighted average price, pro-rata in-kind distribution

3 terms

Rule 10b5-1 trading plan regulatory

"These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

pro-rata in-kind distribution financial

"for no consideration in a pro-rata in-kind distribution."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did CLYM disclose in this Form 4?

Climb Bio director Thomas Stephen Basil disclosed the sale of 100,000 shares of common stock on September 15, 2026, at a weighted average price of $13.6682 per share, in open-market or private transactions.

Was the CLYM insider sale made under a Rule 10b5-1 plan?

Yes. The filing states the transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 16, 2026, indicating the trades were pre-arranged under that plan.

What price range did the CLYM insider receive for the sold shares?

The filing reports a weighted average price of $13.6682 per share, with the individual sale prices ranging from $13.38 to $14.34 per share across multiple transactions on September 15, 2026.

How many CLYM shares does the insider hold after this transaction?

After the reported sale, Thomas Stephen Basil directly holds 467,969 shares of Climb Bio common stock. This total includes 413,312 shares received for no consideration via a pro-rata in-kind distribution from Sera Medicines, LLC.

What is the significance of the 413,312 CLYM shares mentioned in the Form 4?

The filing explains that 413,312 shares of Climb Bio common stock were distributed for no consideration by Sera Medicines, LLC to certain limited partners, including the reporting person, as a pro-rata in-kind distribution.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/17/2026 - 04:15 PM Accepted by SEC EDGAR 09/17/2026 - 04:15 PM Learn about SEC filing dates

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).

X

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^*

Thomas Stephen Basil

(Last) (First) (Middle)

C/O CLIMB BIO, INC.

20 WILLIAM STREET, SUITE G50

(Street)

WELLESLEY HILLS MASSACHUSETTS 02481

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2026

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

X	Form filed by One Reporting Person
	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
Common Stock	09/15/2026		S(1)		100,000	D	$13.6682(2)	467,969(3)	D

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. These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 16, 2026.

2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.3800 to $14.3400, inclusive. The reporting person undertakes to provide the staff of the Securities and Exchange Commission, the issuer or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price within the range.

3. Includes 413,312 shares of the issuer's common stock, par value $0.0001 per share, distributed by Sera Medicines, LLC to certain of its limited partners, including the reporting person, for no consideration in a pro-rata in-kind distribution.

	/s/ Chandra Adams, as Attorney-in-Fact	09/17/2026
	** 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)