Latest Period
Q1 2026
Security Snapshot
Rallybio Corp - Common Stock, par value $0.0001 per share (RLYB) Institutional Ownership
CUSIP: 75120L209
13F Institutional Holders and Ownership History from Q4 2025 to Q1 2026
Institutions Reporting
38
Shares (Excl. Options)
4,666,407
Price
$8.97
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- Security type / class
- Equity / Common Stock, par value $0.0001 per share
- Symbol
- RLYB on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 4,666,407
- Total 13F value
- $41,853,824
- Portfolio coverage rank
- 0%
- Share change
- +4,529,258
- Value change
- +$40,706,436
- Number of holders
- 38
- Shares outstanding
- 5,293,440
- SEC-reported price per share
- $14.52
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
2 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- RLYB - Rallybio Corp - Common Stock, par value $0.0001 per share is tracked under CUSIP 75120L209.
- 38 institutions reported positions in Q1 2026.
- 3 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 1 to 38 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $6,861 to $41,853,824.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 38 institutions filings for Q1 2026.
Security key
75120L209
Latest holder period
Q1 2026
13F holders
38
13D/G owners
3
CIK / CUSIP context first
Open Q1 2026 holders
RLYB full holder history
Rallybio Corp SEC filings
Rallybio Corp company facts
Rallybio Corp insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 75120L209:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
3
Security
RLYB
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| ADAR1 Capital Management, LLC | 18% | $13,293,151 | 926,352 | ADAR1 Capital Management, LLC | 31 May 2026 | |||
| FMR LLC | 11% | +50% | $2,679,776 | +$901,392 | 561,798 | +51% | FMR LLC | 04 Mar 2026 |
| 5AM Ventures V, L.P. | 5.5% | 291,788 | Andrew J. Schwab | 25 Feb 2026 |
As of 31 Mar 2026, 38 institutional investors reported holding 4,666,407 shares of Rallybio Corp - Common Stock, par value $0.0001 per share (RLYB). This represents 88% of the company’s total 5,293,440 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
88%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| FMR LLC | 15% | 793,451 | 0% | $7,117,256 | |
| VIKING GLOBAL INVESTORS LP | 9.9% | 524,347 | 0.01% | $4,703,393 | |
| Cormorant Asset Management, LP | 7.6% | 400,000 | 0.18% | $3,588,000 | |
| TPG GP A, LLC | 7.2% | 378,551 | 0.09% | $3,395,602 | |
| Balyasny Asset Management L.P. | 7.1% | 376,573 | 0.01% | $3,377,860 | |
| Laurion Capital Management LP | 5.7% | 302,756 | 0.25% | $2,715,721 | |
| Nantahala Capital Management, LLC | 5.7% | 300,635 | 0.17% | $2,696,696 | |
| Pivotal bioVenture Partners Investment Advisor LLC | 5.7% | 300,579 | 0.96% | $2,696,194 | |
| 5AM Venture Management, LLC | 5.5% | 291,788 | 0.73% | $2,617,338 | |
| Almitas Capital LLC | 3.6% | 191,206 | 0.39% | $1,715,118 | |
| RENAISSANCE TECHNOLOGIES LLC | 3% | 156,527 | 0% | $1,404,047 | |
| JOHNSON & JOHNSON | 2.9% | 152,901 | 0.21% | $1,371,522 | |
| VANGUARD CAPITAL MANAGEMENT LLC | 2.1% | 112,040 | 0% | 0% | $1,004,999 |
| AJU IB Investment Co., Ltd. | 1.8% | 94,334 | 2.8% | $846,176 | |
| Mariner, LLC | 0.96% | 50,566 | 0% | $453,577 | |
| GEODE CAPITAL MANAGEMENT, LLC | 0.67% | 35,425 | 0% | $317,821 | |
| DELTEC ASSET MANAGEMENT LLC | 0.64% | 33,750 | 0.06% | $302,737 | |
| Rangeley Capital, LLC | 0.57% | 30,130 | 0.29% | $270,266 | |
| GTS SECURITIES LLC | 0.42% | 22,016 | 0.01% | $197,484 | |
| ADAR1 Capital Management, LLC | 0.39% | 20,535 | 0.01% | $184,199 | |
| CITADEL ADVISORS LLC | 0.38% | 19,886 | 0% | $178,377 | |
| BlackRock, Inc. | 0.33% | 17,486 | 0% | $156,849 | |
| VANGUARD FIDUCIARY TRUST CO | 0.26% | 13,547 | 0% | 0% | $121,517 |
| DIMENSIONAL FUND ADVISORS LP | 0.21% | 11,280 | 0% | $101,182 | |
| XTX Topco Ltd | 0.21% | 11,226 | 0% | $100,697 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
2
Latest
Q1 2026
Rows shown
1-2 of 2