Sec Form 4 Filing - HUNT RONALD @ Rallybio Corp - 2021-07-28

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person HUNT RONALD 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) (Last) (First) (Middle) C/O RALLYBIO CORPORATION, 234 CHURCH STREET, SUITE 1020 3. Date of Earliest Transaction (MM/DD/YY) 07/28/2021 (Street) NEW HAVEN, CT06510 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 07/28/2021 J( 1 ) 1,993,911 A 1,993,911 I See footnote ( 2 ) Common Stock 08/02/2021 P 153,846 A $ 13 2,147,757 I See footnote ( 2 ) Common Stock 08/02/2021 P 153,846 A $ 13 2,301,603 I See footnote ( 3 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Series A-1 Preferred Units ( 1 ) 07/28/2021 J( 1 ) 1,795,946 ( 1 ) ( 1 ) Common Stock ( 4 ) 282,044 ( 1 ) 0 I See footnote ( 2 ) Series A-2 Preferred Units ( 1 ) 07/28/2021 J( 1 ) 8,742,654 ( 1 ) ( 1 ) Common Stock ( 4 ) 1,372,989 ( 1 ) 0 I See footnote ( 2 ) Series B Preferred Units ( 1 ) 07/28/2021 J( 1 ) 2,157,838 ( 1 ) ( 1 ) Common Stock ( 4 ) 338,878 ( 1 ) 0 I See footnote ( 2 ) Option (Right to Buy) $ 13 07/28/2021 A 13,440 ( 5 ) ( 5 ) Common Stock 13,440 $ 0 13,440 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other HUNT RONALD C/O RALLYBIO CORPORATION 234 CHURCH STREET, SUITE 1020 NEW HAVEN, CT06510 X Signatures By: /s/ Michael Greco, Attorney-in-Fact 08/04/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Series A-1 Preferred Units, Series A-2 Preferred Units and Series B Preferred Units (collectively, the "Preferred Units") reported herein were preferred units of Rallybio Holdings, LLC. The shares of common stock of the Issuer were received on July 28, 2021 pursuant to the Plan of Liquidation and Dissolution, dated July 28, 2021, among Rallybio Holdings, LLC and its members (the "Plan of Liquidation"). Pursuant to the Plan of Liquidation, the holders of Preferred Units received approximately 6.37 shares of common stock of the Issuer for each Preferred Unit. Rallybio Holdings, LLC was subsequently dissolved. The Preferred Units had no expiration date prior to the liquidation. ( 2 )Shares are directly held by New Leaf Ventures III, L.P. ("NLV-III"). New Leaf Venture Associates III, L.P. ("NLVA-III LP") is the general partner of NLV-III and New Leaf Venture Management III, L.L.C. ("NLVM-III LLC) is the general partner of NLVA-III LP. The Reporting Person is a managing director of NLVM-III LLC and may be deemed to have shared voting, investment and dispositive power with respect to the shares held by NLV-III. The Reporting Person disclaims beneficial ownership of the shares held by NLV-III, except to the extent of his pecuniary interest therein, if any. ( 3 )Shares are directly held by New Leaf Biopharma Opportunities II, L.P. ("NL BPO-II"). New Leaf BPO Associates II, L.P. ("NL BPOA-II LP") is the general partner of NL BPO-II and New Leaf BPO Management II, L.L.C. ("NL BPOA-II LLC) is the general partner of NL BPOA-II LP. The Reporting Person is a managing director of NL BPOA-II LLC and may be deemed to have shared voting, investment and dispositive power with respect to the shares held by NL BPO-II. The Reporting Person disclaims beneficial ownership of the shares held by NL BPO-II, except to the extent of his pecuniary interest therein, if any. ( 4 )Prior to the effectiveness of the Plan of Liquidation, the Preferred Units of Rallybio Holdings, LLC were convertible into shares of common units of Rallybio Holdings, LLC. ( 5 )The option vests as to the underlying shares of Common Stock on the earlier of July 28, 2022 and the date of the first annual meeting of stockholders of the Issuer following the closing of its initial public offering. The option expires on July 28, 2031.

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