5AM Ventures group reports 0% Rallybio (RLYB) ownership after May 4 share sales

Rhea-AI Filing Summary

Rallybio Corp’s major venture backer 5AM Ventures and related entities now report owning no common stock in the company. In this Amendment No. 3 to Schedule 13D, 5AM Ventures V, 5AM Opportunities I and their managing members disclose aggregate beneficial ownership of 0 shares, or 0.0% of Rallybio’s common stock.

The filing notes that on May 4, 2026, 5AM Ventures V sold 135,319 shares and 5AM Opportunities I sold 156,469 shares in open market transactions, at prices between $13.72 and $14.50 per share, with a weighted average sale price of $13.95 per share for each fund.

Insights

Equity ownership & governance analyst

5AM Ventures and affiliates have fully exited their disclosed Rallybio position.

The amendment shows all listed 5AM funds and individuals now report 0 shares and 0.0% beneficial ownership of Rallybio Corp common stock. This reflects a complete exit of their previously reported stake under Schedule 13D.

On May 4, 2026, 5AM Ventures V sold 135,319 shares and 5AM Opportunities I sold 156,469 shares in open market trades, with a weighted average sale price of $13.95 per share within a $13.72–$14.50 range. Future company filings may show how Rallybio’s shareholder base evolves after this venture investor’s departure.

Key Figures

5AM Ventures V sales volume: 135,319 shares 5AM Opportunities I sales volume: 156,469 shares Sale price range: $13.72–$14.50 per share +3 more

6 metrics

5AM Ventures V sales volume 135,319 shares Common stock sold on May 4, 2026 in open market transactions

5AM Opportunities I sales volume 156,469 shares Common stock sold on May 4, 2026 in open market transactions

Sale price range $13.72–$14.50 per share Price range for May 4, 2026 open market sales

Weighted average sale price $13.95 per share Weighted average for May 4, 2026 sales by both funds

Aggregate beneficial ownership per reporter 0.00 shares Row 11 of each reporting person’s cover page

Percent of class per reporter 0.0% Row 13 of each reporting person’s cover page

Key Terms

beneficially owned, sole voting power, sole dispositive power, open market transactions, +1 more

5 terms

beneficially owned financial

"Rows 11 and 13 of each Reporting Person's cover page to this /A set forth the aggregate number of shares of common stock and percentages of the shares of common stock beneficially owned"

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.

sole voting power financial

"Rows 7 through 10 of each Reporting Person's cover page to this /A set forth the number of shares of common stock as to which such Reporting Person has the sole or shared power to vote"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

sole dispositive power financial

"Rows 7 through 10 of each Reporting Person's cover page to this /A set forth the number of shares of common stock as to which such Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

open market transactions financial

"On May 4, 2026, 5AM V sold an aggregate of 135,319 shares in open market transactions at prices ranging from $13.72 to $14.50"

Open market transactions are the buying and selling of a company’s shares or other securities conducted on public exchanges or through the wider market rather than through private deals or negotiated placements. They matter to investors because these trades change supply and demand in real time—like shoppers affecting a store’s inventory—and so can move prices, signal management or investor sentiment, affect liquidity, and alter ownership stakes that influence future returns and risk.

Schedule 13D regulatory

"This Amendment No. 3 (this "Amendment No. 3" or this "/A") amends and supplements the statement on originally filed with the Securities and Exchange Commission"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 3)

Rallybio Corp

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

75120L209

(CUSIP Number)

Lauren A. Daniel
c/o 5AM Venture Management, LLC, 4 Embarcadero Center, Suite 3110
San Francisco, CA, 94111
(415) 993-8570

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

05/04/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

5AM Ventures V, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

5AM Partners V, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

5AM Opportunities I, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

5AM Opportunities I (GP), LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

Andrew J. Schwab

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

Kush Parmar

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP Number(s): 75120L209

1

Name of reporting person

Scott M. Rocklage

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: Rallybio Corp
(c)	Address of Issuer's Principal Executive Offices: 234 CHURCH STREET, SUITE 1020, NEW HAVEN, CONNECTICUT , 06510.
Item 1 Comment: This Amendment No. 3 (this "Amendment No. 3" or this "Schedule 13D/A") amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") on August 12, 2021 and amended on June 7, 2022 and February 27, 2026 (as amended, the "Statement") by the Reporting Persons. Unless otherwise defined herein, capitalized terms used in this Amendment No. 3 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged.
Item 2.	Identity and Background
(a)	This Schedule 13D/A is being filed on behalf of 5AM Ventures V, L.P. ("5AM V"), 5AM Partners V, LLC ("5AM Partners V"), 5AM Opportunities I, L.P. ("5AM Opportunities"), 5AM Opportunities I (GP), LLC ("5AM Opportunities GP"), Andrew J. Schwab ("Schwab"), Dr. Kush Parmar ("Dr. Parmar") and Dr. Scott M. Rocklage ("Dr. Rocklage"). 5AM V, 5AM Partners V, 5AM Opportunities, 5AM Opportunities GP, Schwab, Dr. Parmar and Dr. Rocklage are collectively referred to herein as the "Reporting Persons." The agreement among the Reporting Persons to file this Schedule 13D/A jointly in accordance with Rule 13d-1(k) of the Securities Exchange Act of 1934, as amended, (the "Act") is attached hereto as Exhibit 99.1.
(b)	The principal business and principal business office of the Reporting Persons is 4 Embarcadero Center, Suite 3110, San Francisco, CA 94111.
(c)	The principal business of the Reporting Persons is venture capital investments. Each of the individuals serves as a Managing Member of 5AM Partners V, which is the general partner of 5AM V. Schwab and Dr. Parmar serve as Managing Members of 5AM Opportunities GP, which is the general partner of 5AM Opportunities.
(d)	During the last five years, none of the Reporting Persons has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).
(e)	During the last five years, none of the Reporting Persons was a party to a civil proceeding of a judicial of administrative body of competent jurisdiction or were subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.
(f)	Each of 5AM V, 5AM Partners V, 5AM Opportunities and 5AM Opportunities GP was organized in the state of Delaware and each of the individuals is a citizen of the United States.
Item 5.	Interest in Securities of the Issuer
(a)	Rows 11 and 13 of each Reporting Person's cover page to this Schedule 13D/A set forth the aggregate number of shares of common stock and percentages of the shares of common stock beneficially owned by such Reporting Person. 5AM Partners V is the sole general partner of 5AM V and shares voting and dispositive power over the securities held by 5AM Partners V. 5AM Opportunities GP is the sole general partner of 5AM Opportunities and shares voting and dispositive power over the securities held by 5AM Opportunities. Schwab and Drs. Parmar and Rocklage are the managing members of 5AM Partners V and share voting and dispositive power over the securities held by 5AM V. Schwab and Dr. Parmar are the managing members of 5AM Opportunities GP and share voting and dispositive power over the securities held by 5AM Opportunities.
(b)	Rows 7 through 10 of each Reporting Person's cover page to this Schedule 13D/A set forth the number of shares of common stock as to which such Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition and are incorporated by reference.
(c)	Except as set forth below, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer during the past sixty days. On May 4, 2026, 5AM V sold an aggregate of 135,319 shares in open market transactions at prices ranging from $13.72 to $14.50 (weighted average sales price of $13.95 per share). On May 4, 2026, 5AM Opportunities sold an aggregate of 156,469 shares in open market transactions at prices ranging from $13.72 to $14.50 (weighted average sales price of $13.95 per share).
(d)	No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, the securities beneficially owned by any of the Reporting Persons.
(e)	Not Applicable.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit A to the Reporting Persons' Schedule 13D, filed with the SEC on August 12, 2021).

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.

5AM Ventures V, L.P.

Signature:	/s/ Scott M. Rocklage
Name/Title:	By 5AM Partners V, LLC, its General Partner, By Scott M. Rocklage, Managing Member
Date:	05/06/2026

5AM Partners V, LLC

Signature:	/s/ Scott M. Rocklage
Name/Title:	By Scott M. Rocklage, Managing Member
Date:	05/06/2026

5AM Opportunities I, L.P.

Signature:	/s/ Kush Parmar
Name/Title:	By 5AM Opportunities I (GP), LLC, its General Partner, By Kush Parmar, Managing Member
Date:	05/06/2026

5AM Opportunities I (GP), LLC

Signature:	/s/ Kush Parmar
Name/Title:	By Kush Parmar, Managing Member
Date:	05/06/2026

Andrew J. Schwab

Signature:	/s/ Andrew J. Schwab
Name/Title:	Andrew J. Schwab
Date:	05/06/2026

Kush Parmar

Signature:	/s/ Kush Parmar
Name/Title:	Kush Parmar
Date:	05/06/2026

Scott M. Rocklage

Signature:	/s/ Scott M. Rocklage
Name/Title:	Scott M. Rocklage
Date:	05/06/2026

FAQ

What does the latest Schedule 13D/A say about 5AM Ventures’ stake in Rallybio (RLYB)?

The amendment reports that 5AM Ventures entities and their principals now beneficially own 0 Rallybio common shares, representing 0.0% of the class. This indicates a full exit of their previously disclosed position under Schedule 13D.

How many Rallybio (RLYB) shares did 5AM Ventures V sell in this period?

5AM Ventures V sold an aggregate 135,319 Rallybio common shares on May 4, 2026 in open market transactions. The reported trades occurred at prices ranging from $13.72 to $14.50 per share, with a weighted average sale price of $13.95 per share.

What Rallybio (RLYB) share sales did 5AM Opportunities I report?

5AM Opportunities I, L.P. reported selling 156,469 Rallybio common shares on May 4, 2026 in open market trades. These sales were executed between $13.72 and $14.50 per share, with a weighted average sale price of $13.95 per share disclosed.

What is the current beneficial ownership percentage of Rallybio (RLYB) by the 5AM reporting group?

Each reporting person in the 5AM group lists an aggregate beneficial ownership of 0.00 shares of Rallybio common stock, corresponding to 0.0% of the outstanding class. Rows 11 and 13 on their cover pages present these figures clearly for investors.

Who are the reporting persons in this Rallybio (RLYB) Schedule 13D/A Amendment No. 3?

The reporting persons are 5AM Ventures V, L.P., 5AM Partners V, LLC, 5AM Opportunities I, L.P., 5AM Opportunities I (GP), LLC, Andrew J. Schwab, Dr. Kush Parmar, and Dr. Scott M. Rocklage, all associated with 5AM’s venture capital activities.

What type of transactions did 5AM entities use to sell Rallybio (RLYB) shares?

The filing specifies that 5AM Ventures V and 5AM Opportunities I executed open market transactions on May 4, 2026. These sales were conducted on the market within a price range of $13.72 to $14.50 per Rallybio common share.