Rallybio director exercises options for 2,062 shares

The reported exercise converted options into directly held common shares at a stated price of $15.28 per share.

Rhea-AI Filing Summary

Rallybio Corp (RLYB) director Helen M. Boudreau exercised options to acquire 2,062 common shares at an exercise price of $15.28 per share on October 16, 2026. The reported option position had zero shares remaining after the exercise. Her directly held common-stock position was 8,604 shares afterward.

Insider Trade Summary

2,062 shares exercised/converted

Exercise 2 txns

Insider Boudreau Helen M

Role Director

Type	Security	Shares	Price	Value
Exercise	Option (Right to Buy) F1	2,062	$0.00	$0.00
Exercise	Common Stock	2,062	$15.28	$32K

Holdings After Transaction: Option (Right to Buy) — 0 contracts (Direct); Common Stock — 8,604 shares (Direct)

Footnotes (1)

1. F1. The option was granted under the Company's 2021 Equity Incentive Plan. The option vests on the earlier of May 15, 2025 or the date of the Company's 2025 Annual Meeting of Stockholders.

Key Figures

Common shares acquired through option exercise: 2,062 shares Option exercise price: $15.28 per share Direct common shares after transaction: 8,604 shares +1 more

4 metrics

Common shares acquired through option exercise 2,062 shares October 16, 2026

Option exercise price $15.28 per share October 16, 2026 exercise

Direct common shares after transaction 8,604 shares After the October 16, 2026 exercise

Option expiration May 15, 2034 Reported option

Key Terms

Option (Right to Buy), exercise price, 2021 Equity Incentive Plan

3 terms

Option (Right to Buy) financial

"Option (Right to Buy)"

exercise price financial

"exercise price of $15.28"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

2021 Equity Incentive Plan financial

"granted under the Company's 2021 Equity Incentive Plan"

FAQ

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

How many Rallybio shares did director Helen M. Boudreau acquire through an option exercise?

Helen M. Boudreau exercised options to acquire 2,062 Rallybio common shares at $15.28 per share on October 16, 2026. Her directly held common-stock position was 8,604 shares after the exercise.

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

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Available on EDGAR 10/20/2026 - 05:29 PM EDT Accepted by SEC EDGAR 10/20/2026 - 05:29 PM EDT 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).

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^*

Boudreau Helen M

(Last) (First) (Middle)

C/O RALLYBIO CORPORATION

PO BOX 325

(Street)

EAST BERLIN CONNECTICUT 06023

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Rallybio Corp [ RLYB ]

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)
10/16/2026

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	10/16/2026		M		2,062	A	$15.28	8,604	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
Option (Right to Buy)	$15.28	10/16/2026		M			2,062	(1)	05/15/2034	Common Stock	2,062	$0	0	D

Explanation of Responses:

1. The option was granted under the Company's 2021 Equity Incentive Plan. The option vests on the earlier of May 15, 2025 or the date of the Company's 2025 Annual Meeting of Stockholders.

	By: /s/ Jonathan Lieber, Attorney-in-Fact	10/20/2026
	** 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)