RLYB · Rallybio Corp · Shareholders & Ownership

$16.40 +0.18 (+1.11%) At close · Oct 22

Market Cap

$86.14M

5.31M

Volume · Oct 22 5526 Avg daily vol (3M) 15.41K

Every disclosed holder of RLYB in one list: 13F institutions, Schedule 13D and 13G filers, insiders (Forms 3, 4 and 5) and registered funds, each from its own latest filing. Holders nest by CIK and SEC reporting links, never by name, and each is summed once.

How the holder list picks a filing →

Who Owns RLYB

13F quarter Sep 30, 2026, combined view: filers that have not filed yet carry their Jun 30, 2026 positions

Holder group	Holders	Shares	% Out	Summed
Institutional (13F)	37	4,064,764	76.54%	Yes
Insiders (Forms 3, 4, 5)	7	174,844	3.29%	Yes
13D/G-only blocks	4	931,742	17.55%	Yes
Remaining	—	139,149	2.62%	Rest
Registered funds (N-PORT, not summed)	16	542,614	10.22%	No

Shares outstanding: 5,310,499, the issuer's latest cover-page count restated onto today's split basis.

13D/G-only counts each filer's latest 13D or 13G that no 13F report of the listing contains, that names no 13F filer and that no counted insider files. Funds are never summed: their shares sit inside their advisers' 13F reports.

Holders of RLYB

One row per holder Every filing By ultimate parent

All 13F Funds Insiders 13D/G Non-US

#	Holder	Shares	% Out	Change	As of	Notes
1	ADAR1 Capital Management, LLC 13F CIK 1940272 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	926,352	17.44%	+905,817	Jun 30, 2026	carried, not yet filed for the newest quarter
1.1	ADAR1 Capital Management, LLC Insider CIK 1940272 · May 19, 2026 10% Owner, issuer-wide, not summed	926,352	17.44%	+16,209	May 19, 2026	10% Owner, issuer-wide, not summed
2	FMR LLC 13F CIK 315066 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	794,720	14.97%	+1,269	Jun 30, 2026	carried, not yet filed for the newest quarter
2.1	FMR LLC 13G CIK 315066 · Holding company · Jun 30, 2026 Rule 13d-1(c), passive investor, not summed	794,720	14.97%	+232,922	Jun 30, 2026	Rule 13d-1(c), passive investor, not summed
2.2	FMR LLC Insider CIK 315066 · Mar 4, 2026 10% Owner, issuer-wide, not summed	211,798	3.99%	-1	Mar 4, 2026	10% Owner, issuer-wide, not summed
2.3	Fidelity Growth Company Fund Fund S000007119 · Registered fund · May 31, 2026 Fidelity Mt. Vernon Street Trust, not summed	207,668	3.91%	—	May 31, 2026	Fidelity Mt. Vernon Street Trust, not summed
2.4	Fidelity Growth Company K6 Fund Fund S000065696 · Registered fund · May 31, 2026 Fidelity Mt. Vernon Street Trust, not summed	56,522	1.06%	—	May 31, 2026	Fidelity Mt. Vernon Street Trust, not summed
2.5	Fidelity Series Growth Company Fund Fund S000042626 · Registered fund · May 31, 2026 Fidelity Mt. Vernon Street Trust, not summed	53,600	1.01%	—	May 31, 2026	Fidelity Mt. Vernon Street Trust, not summed
3	VIKING GLOBAL INVESTORS LP 13F CIK 1103804 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	524,347	9.87%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
4	TPG GP A, LLC 13F CIK 1903793 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	378,551	7.13%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
5	Nan Fung Group Holdings Limited 13D CIK 1695076 · Unknown · Feb 12, 2024	300,581	5.66%	—	Feb 12, 2024
6	Pivotal bioVenture Partners Investment Advisor LLC 13F CIK 1844645 · Exempt reporting adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	300,579	5.66%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
7	Canaan XI L.P. 13G CIK 1712417 · Unknown · Jul 29, 2024 Rule 13d-1(d), exempt investor	257,277	4.84%	—	Jul 29, 2024	Rule 13d-1(d), exempt investor
8	NOVO HOLDINGS A/S 13G CIK 1388325 · Unknown · Dec 27, 2023 Rule 13d-1(c), passive investor	220,983	4.16%	—	Dec 27, 2023	Rule 13d-1(c), passive investor
9	RENAISSANCE TECHNOLOGIES LLC 13F CIK 1037389 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	199,907	3.76%	+43,380	Jun 30, 2026	carried, not yet filed for the newest quarter
10	Nantahala Capital Management, LLC 13F CIK 1472322 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	188,422	3.55%	-112,213	Jun 30, 2026	carried, not yet filed for the newest quarter
10.1	Nantahala Capital Management, LLC 13G CIK 1472322 · Registered investment adviser · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	188,422	3.55%	-112,213	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
11	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	172,497	3.25%	+60,457	Jun 30, 2026	carried, not yet filed for the newest quarter
12	JOHNSON & JOHNSON 13G CIK 200406 · Unknown · Mar 31, 2026 Rule 13d-1(c), passive investor	152,901	2.88%	—	Mar 31, 2026	Rule 13d-1(c), passive investor
13	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	134,620	2.54%	+55,150	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
14	Almitas Capital LLC 13F CIK 1596468 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	120,682	2.27%	-70,524	Jun 30, 2026	carried, not yet filed for the newest quarter
15	Uden Stephen Insider CIK 1332141 · Oct 6, 2026 Director, Chief Executive Officer, issuer-wide	115,620	2.18%	+25,729	Oct 6, 2026	Director, Chief Executive Officer, issuer-wide
16	Rangeley Capital, LLC 13F CIK 1517796 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	104,850	1.97%	+74,720	Jun 30, 2026	carried, not yet filed for the newest quarter
17	CITADEL ADVISORS LLC 13F CIK 1423053 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	72,200	1.36%	+52,314	Jun 30, 2026	carried, not yet filed for the newest quarter
18	Mariner, LLC 13F CIK 1373442 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	50,566	0.95%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
19	JANE STREET GROUP, LLC 13F CIK 1595888 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	47,423	0.89%	+47,423	Jun 30, 2026	carried, not yet filed for the newest quarter
20	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	32,447	0.61%	-123	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
21	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	32,047	0.60%	-3,378	Jun 30, 2026	carried, not yet filed for the newest quarter
22	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	30,332	0.57%	+12,846	Jun 30, 2026	carried, not yet filed for the newest quarter
22.1	iShares Micro-Cap ETF Fund S000004439 · Registered fund · Jun 30, 2026 iShares Trust, not summed	11,832	0.22%	—	Jun 30, 2026	iShares Trust, not summed
23	HRT FINANCIAL LP 13F CIK 1475597 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	25,657	0.48%	+25,657	Jun 30, 2026	carried, not yet filed for the newest quarter
24	XTX Topco Ltd 13F CIK 1828301 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	21,497	0.40%	+10,271	Jun 30, 2026	carried, not yet filed for the newest quarter
25	VANGUARD FIDUCIARY TRUST CO 13F CIK 933478 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	16,820	0.32%	+3,273	Jun 30, 2026	carried, not yet filed for the newest quarter
26	TWO SIGMA INVESTMENTS, LP 13F CIK 1179392 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	16,619	0.31%	+16,619	Jun 30, 2026	carried, not yet filed for the newest quarter
27	Hopfner Robert Lorne Insider CIK 1551966 · Oct 12, 2026 Director, issuer-wide	14,820	0.28%	—	Oct 12, 2026	Director, issuer-wide
28	Lieber Jonathan I Insider CIK 1350090 · Oct 9, 2026 Chief Financial Officer, issuer-wide	13,650	0.26%	+3,910	Oct 9, 2026	Chief Financial Officer, issuer-wide
29	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	12,996	0.24%	+12,996	Jun 30, 2026	carried, not yet filed for the newest quarter
30	Quadrature Capital Ltd 13F CIK 1651424 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	12,995	0.24%	+12,995	Jun 30, 2026	carried, not yet filed for the newest quarter
31	Liu Hui Insider CIK 1790518 · Sep 24, 2026 Director, issuer-wide	12,044	0.23%	—	Sep 24, 2026	Director, issuer-wide
32	DIMENSIONAL FUND ADVISORS LP 13F CIK 354204 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	11,280	0.21%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
32.1	Dimensional U.S. Small Cap ETF Fund S000070906 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	6,675	0.13%	0	Jul 31, 2026	Dimensional ETF Trust, not summed
32.2	U.S. MICRO CAP PORTFOLIO Fund S000000948 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	4,605	0.09%	0	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
32.3	Dimensional U.S. Core Equity 2 ETF Fund S000070903 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	578	0.01%	—	Jul 31, 2026	Dimensional ETF Trust, not summed
33	Boudreau Helen M Insider CIK 1661481 · Oct 16, 2026 Director, issuer-wide	8,604	0.16%	+2,062	Oct 16, 2026	Director, issuer-wide
34	Soteropoulos Paula Insider CIK 1692444 · Oct 16, 2026 Director, issuer-wide	6,544	0.12%	+3,559	Oct 16, 2026	Director, issuer-wide
35	Chung Wendy Insider CIK 1922605 · Sep 16, 2026 Director, issuer-wide	3,562	0.07%	—	Sep 16, 2026	Director, issuer-wide
36	VANGUARD INSTITUTIONAL TOTAL STOCK MARKET INDEX FUND Fund S000002855 · Registered fund · Jun 30, 2026 VANGUARD INSTITUTIONAL INDEX FUNDS, not summed	3,141	0.06%	—	Jun 30, 2026	VANGUARD INSTITUTIONAL INDEX FUNDS, not summed
37	VANGUARD BALANCED INDEX FUND Fund S000002560 · Registered fund · Jun 30, 2026 VANGUARD VALLEY FORGE FUNDS, not summed	2,289	0.04%	—	Jun 30, 2026	VANGUARD VALLEY FORGE FUNDS, not summed
38	Vanguard Global Advisers, LLC 13F CIK 1811242 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,442	0.03%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
39	Hartford Financial Management Inc. 13F CIK 1352526 · Registered investment adviser · Sep 30, 2026	812	0.02%	0	Sep 30, 2026
40	1290 VT Micro Cap Portfolio Fund S000044688 · Registered fund · Jun 30, 2026 EQ Advisors Trust, not summed	795	0.02%	—	Jun 30, 2026	EQ Advisors Trust, not summed
41	Caitong International Asset Management Co., Ltd 13F CIK 1963355 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	434	0.01%	+434	Jun 30, 2026	carried, not yet filed for the newest quarter
42	UBS Group AG 13F CIK 1610520 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	146	0.00%	-7,768	Jun 30, 2026	carried, not yet filed for the newest quarter
43	Truvestments Capital LLC 13F CIK 1750405 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	129	0.00%	+129	Jun 30, 2026	carried, not yet filed for the newest quarter
44	MORGAN STANLEY 13F CIK 895421 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	125	0.00%	-1	Jun 30, 2026	carried, not yet filed for the newest quarter
45	BNP PARIBAS ARBITRAGE, SA 13F CIK 1166588 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	120	0.00%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
46	SBI Securities Co., Ltd. 13F CIK 1851815 · Non-US institution · Sep 30, 2026	77	0.00%	-429	Sep 30, 2026
47	Fortitude Family Office, LLC 13F CIK 1950506 · Registered investment adviser · Sep 30, 2026	53	0.00%	0	Sep 30, 2026
48	WELLS FARGO & COMPANY/MN 13F CIK 72971 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	37	0.00%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
49	EverSource Wealth Advisors, LLC 13F CIK 1710537 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	31	0.00%	+31	Jun 30, 2026	carried, not yet filed for the newest quarter
50	JPMORGAN CHASE & CO 13F CIK 19617 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	9	0.00%	-2,488	Jun 30, 2026	carried, not yet filed for the newest quarter

4 more nested rows are not shown here; Every filing lists them all.

Shares are restated onto today's split basis. Change compares each row with the same holder's previous filing in the same source; a dash means there is none to compare. Nested 13D/G, insider and fund rows are not summed, since a 13F report already holds them.

Showing 1–50 of 53 holders

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Key facts CIK 1739410 CUSIP 75120L209 13F (30d) 3 filings 3 filers Visit website Investor relations