RLYB · Rallybio Corp

$16.88 -0.01 (-0.03%) At close · Aug 26

Market Cap

$89.64M

5.31M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Quarter:

Holders: 37

Total Value: $76,620,378

Total Shares: 11,698,780

Institutional Ownership Trend

20 quarters

Superinvestors Holding RLYB

All superinvestors →

Andreas Halvorsen $8,389,552

Holder Concentration

Across 37 13F filers · Δ vs Mar 31, 2026

Top Holder

19.3%

+2.3 pts

Top 5

71.4%

+18.4 pts

Top 10

91.9%

+9.2 pts

HHI

1,208

Broadly held+372

Quarterly Activity

vs Mar 31, 2026

New

Increased

Decreased

Sold Out

Unchanged

Holder count: -1

Institutional value: +83.0%

Shares held: +150.7%

Top Buyers

vs Mar 31, 2026

Institution	Added	Now Holds
Mega CITADEL ADVISORS LLC	+7,685,901	7,705,787
Mid ADAR1 Capital Management, LLC	+905,817	926,352
Small Rangeley Capital, LLC	+74,720	104,850
Mega VANGUARD CAPITAL MANAGEMENT LLC	+60,457	172,497
Large RENAISSANCE TECHNOLOGIES LLC	+43,380	199,907

Top Sellers

vs Mar 31, 2026

Institution	Sold	Now Holds
Mid Nantahala Capital Management, LLC	−112,213	188,422
Small Almitas Capital LLC	−70,524	120,682
Mega UBS Group AG	−7,768	146
Mega GEODE CAPITAL MANAGEMENT, LLC	−3,378	32,047
Mega JPMORGAN CHASE & CO	−2,488	9

Top New Positions

vs Mar 31, 2026

Institution	Acquired	Value (USD)
Mega JANE STREET GROUP, LLC	47,423	$758,768
Large HRT FINANCIAL LP	25,657	$410,512
Mega TWO SIGMA INVESTMENTS, LP	16,619	$265,904
Mega STATE STREET CORP	12,996	$207,936
Large Quadrature Capital Ltd	12,995	$207,920

Top Sold-Out Positions

vs Mar 31, 2026

Institution	Previously Held	Last Value (USD)
Mid Cormorant Asset Management, LP	400,000	$3,588,000
Large Balyasny Asset Management L.P.	376,573	$3,377,859
Mid Laurion Capital Management LP	302,756	$2,715,721
Small 5AM Venture Management, LLC	291,788	$2,617,338
Small JOHNSON & JOHNSON	152,901	$1,371,521

Filter: New 9 Increased 9 Reduced 7 Sold out 10 Unchanged 12

Showing 37 of 37

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

ADAR1 Capital Management, LLC

$14,821,632

19.34%

926,352

CITADEL ADVISORS LLC

$12,732,490

16.62%

7,705,787

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	71,980	$1,151,680	9.0%	Defined
Held directly	7,633,807	$11,580,810	91.0%	Defined

FMR LLC

$12,715,520

16.60%

794,720

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Fidelity Management & Research Co LLC	317,790	$5,084,640	40.0%	Defined
FIDELITY MANAGEMENT TRUST CO	265,132	$4,242,112	33.4%	Defined
Impresa Management LLC	211,798	$3,388,768	26.7%	Defined

VIKING GLOBAL INVESTORS LP

$8,389,552

10.95%

524,347

TPG GP A, LLC

$6,056,816

7.90%

378,551

Pivotal bioVenture Partners Investment Advisor LLC

$4,809,264

6.28%

300,579

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Pivotal bioVenture Partners Fund I U.G.P. Ltd	300,579	$4,809,264	100.0%	Defined

RENAISSANCE TECHNOLOGIES LLC

$3,198,512

4.17%

199,907

Nantahala Capital Management, LLC

$3,014,752

3.93%

188,422

VANGUARD CAPITAL MANAGEMENT LLC

$2,759,952

3.60%

172,497

Almitas Capital LLC

$1,930,912

2.52%

120,682

Rangeley Capital, LLC

$1,677,600

2.19%

104,850

Mariner, LLC

$809,056

1.06%

50,566

JANE STREET GROUP, LLC

$758,768

0.99%

47,423

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	33,844	$541,504	71.4%	Defined
Jane Street Global Trading, LLC	13,579	$217,264	28.6%	Defined

GEODE CAPITAL MANAGEMENT, LLC

$512,752

0.67%

32,047

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GEODE CAPITAL MANAGEMENT TRUST COMPANY, LLC	6,567	$105,072	20.5%	Defined
Held directly	25,480	$407,680	79.5%	Defined

BlackRock, Inc.

$485,312

0.63%

30,332

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BlackRock Investment Management, LLC	795	$12,720	2.6%	Sole
BlackRock Fund Advisors	11,832	$189,312	39.0%	Sole
BlackRock Institutional Trust Company, N.A.	17,705	$283,280	58.4%	Sole

HRT FINANCIAL LP

$410,512

0.54%

25,657

XTX Topco Ltd

$343,952

0.45%

21,497

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
XTX EXECUTION SERVICES LLC joint	21,497	$343,952	100.0%	Defined

VANGUARD FIDUCIARY TRUST CO

$269,120

0.35%

16,820

TWO SIGMA INVESTMENTS, LP

$265,904

0.35%

16,619

STATE STREET CORP

$207,936

0.27%

12,996

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
STATE STREET GLOBAL ADVISORS TRUST COMPANY	12,996	$207,936	100.0%	Defined

Quadrature Capital Ltd

$207,920

0.27%

12,995

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Quadrature US Inc.	12,995	$207,920	100.0%	Other

DIMENSIONAL FUND ADVISORS LP

$180,480

0.24%

11,280

Vanguard Global Advisers, LLC

$23,072

0.03%

1,442

Hartford Financial Management Inc.

$12,992

0.02%

812

SBI Securities Co., Ltd.

$8,096

0.01%

506

Caitong International Asset Management Co., Ltd

$6,944

0.01%

434

UBS Group AG

$2,336

0.00%

146

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS AG	146	$2,336	100.0%	Defined

Truvestments Capital LLC

$2,064

0.00%

129

MORGAN STANLEY

$2,000

0.00%

125

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY SMITH BARNEY LLC	125	$2,000	100.0%	Defined

BNP PARIBAS ARBITRAGE, SA

$1,920

0.00%

120

Fortitude Family Office, LLC

$848

0.00%

WELLS FARGO & COMPANY/MN

$592

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
WELLS FARGO CLEARING SERVICES, LLC	37	$592	100.0%	Defined

EverSource Wealth Advisors, LLC

$496

0.00%

JPMORGAN CHASE & CO

$144

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
J.P. Morgan Securities plc	9	$144	100.0%	Defined

Allworth Financial LP

$96

0.00%

BARCLAYS PLC

$48

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BARCLAYS CAPITAL INC.	3	$48	100.0%	Defined

DANSKE BANK A/S

$16

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Chen Bihua	400,000	$3,588,000	100.0%	Defined

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Johnson & Johnson Innovation - JJDC, Inc.	152,901	$1,371,521	100.0%	Defined

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Acadian Inc	10,433	$93,584	100.0%	Defined

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Latour Trading LLC (Latour)	907	$8,135	100.0%	Defined

Key facts CIK 1739410 CUSIP 75120L209 13F (30d) 38 filings 36 filers Visit website Investor relations