RallyBio Corporation: Nantahala Capital Management, LLC and its principals, Wilmot B. Harkey and Daniel Mack, report beneficial ownership of 300,635 shares of RallyBio Common Stock, representing 5.68% of the class as of March 31, 2026.
The filing states the reported shares are held by funds and separately managed accounts under Nantahala's control and that the Reporting Persons have shared voting and dispositive power over these shares.
Positive
None.
Negative
None.
Insights
Nantahala reports a 5.68% passive stake in RallyBio as of March 31, 2026.
The Schedule 13G shows Nantahala and its named principals beneficially own 300,635 shares with shared voting and dispositive power, consistent with an investment-adviser reporting posture rather than an active takeover intent.
Key dependencies include whether the stake changes in subsequent filings and any shifts from passive to active investor status; subsequent filings would disclose such changes.
Key Figures
Shares beneficially owned:300,635 sharesPercent of class:5.68%CUSIP:75120L209+1 more
4 metrics
Shares beneficially owned300,635 sharesAs of March 31, 2026
Percent of class5.68%As of March 31, 2026
CUSIP75120L209RallyBio Common Stock identifier
Filing signature date05/15/2026Schedule signed by Reporting Persons and CCO
"Each of Messrs. Harkey and Mack is filing this as a control person in respect of shares beneficially owned by Nantahala"
A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.
beneficially ownedfinancial
"As of March 31, 2026, Nantahala may be deemed to be the beneficial owner of 300,635 Shares"
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.
shared voting powerregulatory
"Shared Voting Power 300,635.00 and Shared Dispositive Power 300,635.00"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
investment adviserregulatory
"Nantahala, an investment adviser as described in ss. 240.13d-1(b)(1)(ii)(E)"
An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
RALLYBIO CORPORATION
(Name of Issuer)
Common Stock, par value $0.0001 per share
(Title of Class of Securities)
75120L209
(CUSIP Number)
03/31/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
75120L209
1
Names of Reporting Persons
Nantahala Capital Management, LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
MASSACHUSETTS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
300,635.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
300,635.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
300,635.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.68 %
12
Type of Reporting Person (See Instructions)
IA
SCHEDULE 13G
CUSIP Number(s):
75120L209
1
Names of Reporting Persons
Wilmot B. Harkey
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
300,635.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
300,635.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
300,635.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.68 %
12
Type of Reporting Person (See Instructions)
HC
SCHEDULE 13G
CUSIP Number(s):
75120L209
1
Names of Reporting Persons
Daniel Mack
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
300,635.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
300,635.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
300,635.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.68 %
12
Type of Reporting Person (See Instructions)
HC
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
RALLYBIO CORPORATION
(b)
Address of issuer's principal executive offices:
234 CHURCH STREET NEW HAVEN, CONNECTICUT, 06510
Item 2.
(a)
Name of person filing:
(1) Nantahala Capital Management, LLC ("Nantahala")
(2) Wilmot B. Harkey
(3) Daniel Mack (together the "Reporting Persons")
(b)
Address or principal business office or, if none, residence:
130 Main St. 2nd Floor, New Canaan, Connecticut 06840
(c)
Citizenship:
(1) Nantahala is a Massachusetts limited liability company.
(2) Each of Messrs. Harkey and Mack is a citizen of the United States of America.
(d)
Title of class of securities:
Common Stock, par value $0.0001 per share
(e)
CUSIP Number(s):
75120L209
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
As of March 31, 2026, Nantahala may be deemed to be the beneficial owner of 300,635 Shares held by funds and separately managed accounts under its control, and as the managing members of Nantahala, each of Messrs. Harkey and Mack may be deemed to be a beneficial owner of those Shares.
(b)
Percent of class:
As of March 31, 2026, each of the Reporting Persons may be deemed to be the beneficial owner of the following percentage of the total number of Shares outstanding:
(1) Nantahala Capital Management, LLC ("Nantahala") : 5.68%
(2) Wilmot B. Harkey: 5.68%
(3) Daniel Mack: 5.68%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
(1) Nantahala Capital Management, LLC ("Nantahala") : 0 Shares.
(2) Wilmot B. Harkey: 0 Shares.
(3) Daniel Mack: 0 Shares.
(ii) Shared power to vote or to direct the vote:
(1) Nantahala Capital Management, LLC ("Nantahala") : 300,635 Shares.
(2) Wilmot B. Harkey: 300,635 Shares.
(3) Daniel Mack: 300,635 Shares.
(iii) Sole power to dispose or to direct the disposition of:
(1) Nantahala Capital Management, LLC ("Nantahala") : 0 Shares.
(2) Wilmot B. Harkey: 0 Shares.
(3) Daniel Mack: 0 Shares.
(iv) Shared power to dispose or to direct the disposition of:
(1) Nantahala Capital Management, LLC ("Nantahala") : 300,635 Shares.
(2) Wilmot B. Harkey: 300,635 Shares.
(3) Daniel Mack: 300,635 Shares.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary.
Each of Messrs. Harkey and Mack is filing this Schedule 13G as a control person in respect of shares beneficially owned by Nantahala, an investment adviser as described in ss. 240.13d-1(b)(1)(ii)(E). See Item 4(a).
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
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.
