Rallybio (RLYB)
Rallybio on one page: short interest, daily short volume, fails to deliver, large holders, 13F holders, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as pharmaceutical preparations.
41K
Short interest
settlement 2026-10-15
7.4
Days to cover
+2.5 days vs prior
48.1%
Short share of volume
2026-11-02
149
Fails to deliver
settlement 2026-10-09
Thu 5 Nov
Next earnings
estimated date
-$10K
Insider flow, 90 days
0 buys, 1 sells
As of 2026-11-02.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in RLYB is 40,962 shares, down 14,594 shares over the last month. Over the last 48 readings it ranged from 38,974 shares (13 February 2026) to 1,975,093 shares (15 July 2025). The latest reading sits at the bottom of that range. At the reported average volume of 6K shares a day that is 7.4 days to cover.
Embed this chart.The embed keeps its attribution line.
<iframe src="https://xoomar.com/embed/stocks/rlyb" width="100%" height="440" style="border:0;max-width:100%" loading="lazy" title="XOOMAR chart"></iframe>
| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 40,962 | -16.8% | 5,544 | 7.39 |
| 2026-09-30 | 49,245 | -11.4% | 10,095 | 4.88 |
| 2026-09-15 | 55,556 | +1.1% | 11,022 | 5.04 |
| 2026-08-31 | 54,943 | +0.7% | 9,996 | 5.50 |
| 2026-08-14 | 54,564 | -14.1% | 26,981 | 2.02 |
| 2026-07-31 | 63,485 | -62.7% | 30,844 | 2.06 |
| 2026-07-15 | 170,156 | -58.4% | 48,124 | 3.54 |
| 2026-06-30 | 408,746 | -3.8% | 47,572 | 8.59 |
| 2026-06-15 | 425,033 | -27.6% | 86,454 | 4.92 |
| 2026-05-29 | 586,906 | +1.4% | 48,977 | 11.98 |
| 2026-05-15 | 578,792 | -63.2% | 1,001,411 | 1.00 |
| 2026-04-30 | 1,572,902 | +11.9% | 54,522 | 28.85 |
| 2026-04-15 | 1,405,893 | +26.8% | 68,044 | 20.66 |
| 2026-03-31 | 1,108,870 | +39.0% | 108,393 | 10.23 |
| 2026-03-13 | 797,895 | +1692.3% | 499,683 | 1.60 |
| 2026-02-27 | 44,517 | +14.2% | 89,587 | 1.00 |
| 2026-02-13 | 38,974 | -72.5% | 24,991 | 1.56 |
| 2026-01-30 | 141,643 | +21.5% | 169,162 | 1.00 |
| 2026-01-15 | 116,605 | +9.8% | 118,793 | 1.00 |
| 2025-12-31 | 106,204 | -13.4% | 223,073 | 1.00 |
| 2025-12-15 | 122,587 | -12.7% | 153,372 | 1.00 |
| 2025-11-28 | 140,389 | -19.6% | 201,521 | 1.00 |
| 2025-11-14 | 174,572 | -24.1% | 210,573 | 1.00 |
| 2025-10-31 | 229,838 | -19.1% | 286,823 | 1.00 |
| 2025-10-15 | 284,270 | -14.3% | 329,252 | 1.00 |
| 2025-09-30 | 331,509 | -21.5% | 320,243 | 1.04 |
| 2025-09-15 | 422,184 | -31.1% | 367,311 | 1.15 |
| 2025-08-29 | 612,420 | -20.7% | 307,832 | 1.99 |
| 2025-08-15 | 771,851 | -42.7% | 552,788 | 1.40 |
| 2025-07-31 | 1,346,454 | -31.8% | 557,460 | 2.42 |
| 2025-07-15 | 1,975,093 | +470.2% | 16,128,056 | 1.00 |
| 2025-06-30 | 346,362 | +5.0% | 184,117 | 1.88 |
| 2025-06-13 | 330,040 | +3.5% | 462,974 | 1.00 |
| 2025-05-30 | 318,870 | -10.7% | 92,129 | 3.46 |
| 2025-05-15 | 356,942 | -1.8% | 72,227 | 4.94 |
| 2025-04-30 | 363,424 | +3.4% | 89,099 | 4.08 |
| 2025-04-15 | 351,626 | +1.6% | 295,603 | 1.19 |
| 2025-03-31 | 345,912 | +2.4% | 46,374 | 7.46 |
| 2025-03-14 | 337,792 | +0.1% | 41,994 | 8.04 |
| 2025-02-28 | 337,529 | +1.9% | 60,140 | 5.61 |
| 2025-02-14 | 331,091 | -5.5% | 85,590 | 3.87 |
| 2025-01-31 | 350,193 | -1.1% | 44,607 | 7.85 |
| 2025-01-15 | 353,893 | -0.0% | 66,006 | 5.36 |
| 2024-12-31 | 353,969 | +4.8% | 127,678 | 2.77 |
| 2024-12-13 | 337,653 | -4.6% | 110,305 | 3.06 |
| 2024-11-29 | 354,056 | -3.5% | 59,445 | 5.96 |
| 2024-11-15 | 367,036 | -20.8% | 70,997 | 5.17 |
| 2024-10-31 | 463,356 | -13.7% | 97,650 | 4.75 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of RLYB volume is 48.1%, up 37.8 points over the last five sessions. Over the last 30 readings it ranged from 5.0% (12 October 2026) to 87.0% (29 October 2026). The latest reading is 15.5 points above the 30-session average of 32.6%, on 34K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 17K | 34K | 48.1% | 10,524 |
| 2026-10-30 | 3K | 26K | 10.4% | 0 |
| 2026-10-29 | 22K | 26K | 87.0% | 15,827 |
| 2026-10-28 | 4K | 8K | 48.1% | 0 |
| 2026-10-27 | 8K | 12K | 66.1% | 7,073 |
| 2026-10-26 | 121 | 1K | 10.3% | 0 |
| 2026-10-23 | 654 | 2K | 26.7% | 0 |
| 2026-10-22 | 772 | 2K | 42.8% | 0 |
| 2026-10-21 | 464 | 5K | 8.5% | 0 |
| 2026-10-20 | 118 | 485 | 24.3% | 0 |
| 2026-10-19 | 1K | 4K | 29.1% | 0 |
| 2026-10-16 | 2K | 4K | 47.9% | 0 |
| 2026-10-15 | 540 | 1K | 45.0% | 0 |
| 2026-10-14 | 469 | 2K | 27.7% | 0 |
| 2026-10-13 | 54 | 761 | 7.1% | 0 |
| 2026-10-12 | 100 | 2K | 5.0% | 0 |
| 2026-10-09 | 2K | 2K | 74.9% | 0 |
| 2026-10-08 | 359 | 1K | 29.6% | 0 |
| 2026-10-07 | 891 | 2K | 43.4% | 0 |
| 2026-10-06 | 82 | 266 | 30.8% | 0 |
| 2026-10-05 | 124 | 655 | 18.9% | 0 |
| 2026-10-02 | 537 | 3K | 17.8% | 0 |
| 2026-10-01 | 185 | 3K | 6.0% | 0 |
| 2026-09-30 | 123 | 601 | 20.5% | 0 |
| 2026-09-29 | 253 | 2K | 11.5% | 0 |
| 2026-09-28 | 2K | 5K | 39.7% | 0 |
| 2026-09-25 | 669 | 2K | 39.1% | 0 |
| 2026-09-24 | 547 | 2K | 30.4% | 0 |
| 2026-09-23 | 233 | 345 | 67.5% | 0 |
| 2026-09-22 | 173 | 1K | 13.3% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 9 October 2026, the fails-to-deliver balance in RLYB is 149 shares, down 46 shares over the last settlement date. Over the last 30 readings it ranged from 3 shares (18 May 2026) to 6,744 shares (26 June 2026). The latest reading sits at the bottom of that range.
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-09 | 149 | $16.99 | $3K |
| 2026-10-08 | 195 | $16.93 | $3K |
| 2026-09-21 | 232 | $17.19 | $4K |
| 2026-09-17 | 502 | $17.09 | $9K |
| 2026-09-04 | 12 | $16.88 | $203 |
| 2026-09-02 | 1,213 | $16.69 | $20K |
| 2026-08-20 | 15 | $17.00 | $255 |
| 2026-08-10 | 54 | $16.16 | $873 |
| 2026-08-07 | 52 | $16.19 | $842 |
| 2026-08-03 | 9 | $15.93 | $143 |
| 2026-07-31 | 19 | $16.07 | $305 |
| 2026-07-28 | 65 | $16.31 | $1K |
| 2026-07-27 | 245 | $16.31 | $4K |
| 2026-07-17 | 600 | $15.96 | $10K |
| 2026-06-26 | 6,744 | $15.71 | $106K |
| 2026-06-24 | 54 | $15.70 | $848 |
| 2026-06-17 | 46 | $15.90 | $731 |
| 2026-06-05 | 2,366 | $16.20 | $38K |
| 2026-05-29 | 173 | $14.52 | $3K |
| 2026-05-28 | 178 | $14.53 | $3K |
| 2026-05-27 | 183 | $14.70 | $3K |
| 2026-05-26 | 5,112 | $15.88 | $81K |
| 2026-05-22 | 367 | $15.38 | $6K |
| 2026-05-21 | 601 | $14.58 | $9K |
| 2026-05-19 | 4,579 | $14.10 | $65K |
| 2026-05-18 | 3 | $14.30 | $43 |
| 2026-05-15 | 5,737 | $14.21 | $82K |
| 2026-05-14 | 6,547 | $14.35 | $94K |
| 2026-05-13 | 1,595 | $14.03 | $22K |
| 2026-05-11 | 1,816 | $14.38 | $26K |
Insider trades
SEC Form 4, newest first. JSONInsiders at RLYB reported 1 open-market sell worth $10K in the last 90 days and no open-market buys. Latest filing: HUNT RONALD (Director) on 2026-10-29.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-10-29 | HUNT RONALD | Director | Exercise or conversion | 2K | $15.28 | $32K | 15K |
| 2026-10-29 | HUNT RONALD | Director | Exercise or conversion | 9K | $7.60 | $70K | 13K |
| 2026-10-29 | HUNT RONALD | Director | Exercise or conversion | 4K | $2.38 | $8K | 4K |
| 2026-10-29 | Lieber Jonathan I | Chief Financial Officer | Exercise or conversion | 14K | $6.08 | $83K | 37K |
| 2026-10-29 | Lieber Jonathan I | Chief Financial Officer | Exercise or conversion | 8K | $14.88 | $117K | 23K |
| 2026-10-28 | Nash Christine A | Director | Exercise or conversion | 4K | $2.38 | $8K | 4K |
| 2026-10-27 | Uden Stephen | Chief Executive Officer | Exercise or conversion | 33K | $6.08 | $202K | 149K |
| 2026-10-27 | Lieber Jonathan I | Chief Financial Officer | Sell | 599 | $16.04 | $10K | 16K |
| 2026-10-26 | Lieber Jonathan I | Chief Financial Officer | Grant | 3K | $0.00 | $0 | 16K |
| 2026-10-26 | Chung Wendy | Director | Exercise or conversion | 2K | $15.28 | $32K | 6K |
| 2026-10-16 | Soteropoulos Paula | Director | Exercise or conversion | 4K | $2.38 | $8K | 7K |
| 2026-10-16 | Boudreau Helen M | Director | Exercise or conversion | 2K | $15.28 | $32K | 9K |
| 2026-10-12 | Hopfner Robert Lorne | Director | Exercise or conversion | 2K | $15.28 | $32K | 15K |
| 2026-10-12 | Hopfner Robert Lorne | Director | Exercise or conversion | 4K | $2.38 | $8K | 13K |
| 2026-10-12 | Hopfner Robert Lorne | Director | Exercise or conversion | 9K | $7.60 | $70K | 9K |
| 2026-10-09 | Lieber Jonathan I | Chief Financial Officer | Exercise or conversion | 4K | $6.08 | $24K | 14K |
| 2026-10-06 | Uden Stephen | Chief Executive Officer | Exercise or conversion | 22K | $6.08 | $137K | 116K |
| 2026-09-29 | Lieber Jonathan I | Chief Financial Officer | Exercise or conversion | 5K | $6.08 | $30K | 10K |
| 2026-09-24 | Liu Hui | Director | Exercise or conversion | 8K | $7.60 | $64K | 12K |
| 2026-09-24 | Liu Hui | Director | Exercise or conversion | 4K | $2.38 | $8K | 4K |
| 2026-09-16 | Chung Wendy | Director | Exercise or conversion | 4K | $2.38 | $8K | 4K |
| 2026-07-06 | Boudreau Helen M | Director | Exercise or conversion | 4K | $2.38 | $8K | 7K |
| 2026-05-19 | ADAR1 Capital Management, LLC | 10% owner | Buy | 200 | $13.80 | $3K | 926K |
| 2026-05-19 | ADAR1 Capital Management, LLC | 10% owner | Buy | 10K | $13.98 | $140K | 926K |
| 2026-05-18 | ADAR1 Capital Management, LLC | 10% owner | Buy | 6K | $13.98 | $84K | 916K |
| 2026-05-15 | Schneeberger Daniel | TenPercentOwner | Buy | 100 | $13.80 | $1K | 910K |
| 2026-05-15 | Schneeberger Daniel | TenPercentOwner | Buy | 200 | $13.95 | $3K | 910K |
| 2026-05-15 | ADAR1 Capital Management, LLC | 10% owner | Buy | 200 | $13.95 | $3K | 910K |
| 2026-05-15 | ADAR1 Capital Management, LLC | 10% owner | Buy | 100 | $13.80 | $1K | 910K |
| 2026-05-13 | Schneeberger Daniel | TenPercentOwner | Buy | 75K | $14.00 | $1.1M | 910K |
| 2026-05-13 | Schneeberger Daniel | TenPercentOwner | Buy | 4K | $13.80 | $56K | 835K |
| 2026-05-13 | ADAR1 Capital Management, LLC | 10% owner | Buy | 75K | $14.00 | $1.1M | 910K |
| 2026-05-13 | ADAR1 Capital Management, LLC | 10% owner | Buy | 4K | $13.80 | $56K | 835K |
| 2026-05-12 | ADAR1 Capital Management, LLC | 10% owner | Buy | 800 | $13.83 | $11K | 831K |
| 2026-05-11 | ADAR1 Capital Management, LLC | 10% owner | Buy | 20K | $14.00 | $279K | 830K |
| 2026-05-11 | ADAR1 Capital Management, LLC | 10% owner | Buy | 25K | $14.00 | $350K | 810K |
| 2026-05-11 | ADAR1 Capital Management, LLC | 10% owner | Buy | 5K | $14.00 | $71K | 785K |
| 2026-05-05 | Schneeberger Daniel | TenPercentOwner | Buy | 35K | $14.00 | $491K | 780K |
| 2026-05-05 | ADAR1 Capital Management, LLC | 10% owner | Buy | 35K | $14.00 | $491K | 780K |
| 2026-05-04 | Schneeberger Daniel | TenPercentOwner | Buy | 117K | $13.97 | $1.6M | 745K |
| 2026-05-04 | Schneeberger Daniel | TenPercentOwner | Buy | 4K | $13.90 | $54K | 628K |
| 2026-05-04 | ADAR1 Capital Management, LLC | 10% owner | Buy | 117K | $13.97 | $1.6M | 745K |
| 2026-05-04 | ADAR1 Capital Management, LLC | 10% owner | Buy | 4K | $13.90 | $54K | 628K |
| 2026-02-23 | Lieber Jonathan I | Chief Financial Officer | Sell | 789 | $5.06 | $4K | 4K |
| 2026-02-18 | Lieber Jonathan I | Chief Financial Officer | Grant | 3K | $0.00 | $0 | 5K |
| 2023-03-14 | Lieber Jonathan I | See Remarks | Buy | 5K | $5.21 | $26K | 5K |
| 2023-03-07 | Schwab Andrew J. | TenPercentOwner | Sell | 100K | $8.20 | $820K | 2.4M |
| 2023-03-07 | PARMAR KUSH | Director | Sell | 100K | $8.20 | $820K | 2.4M |
| 2022-06-03 | 5AM Partners V, LLC | TenPercentOwner | Sell | 100K | $12.50 | $1.2M | 2.5M |
| 2022-06-03 | 5AM Partners V, LLC | TenPercentOwner | Sell | 50K | $12.50 | $629K | 1.3M |
| 2022-06-03 | PARMAR KUSH | Director,TenPercentOwner | Sell | 50K | $12.50 | $629K | 1.3M |
| 2022-06-03 | PARMAR KUSH | Director,TenPercentOwner | Sell | 100K | $12.50 | $1.2M | 2.5M |
| 2022-05-23 | 5AM Partners V, LLC | TenPercentOwner | Sell | 66K | $13.00 | $864K | 2.6M |
| 2022-05-23 | 5AM Partners V, LLC | TenPercentOwner | Sell | 34K | $13.00 | $436K | 1.3M |
| 2022-05-23 | PARMAR KUSH | Director,TenPercentOwner | Sell | 34K | $13.00 | $436K | 1.3M |
| 2022-05-23 | PARMAR KUSH | Director,TenPercentOwner | Sell | 66K | $13.00 | $864K | 2.6M |
| 2022-03-21 | Fryer Jeffrey M | See Remarks | Buy | 3K | $8.04 | $24K | 47K |
| 2022-02-08 | PARMAR KUSH | Director | Sell | 70K | $13.05 | $920K | 1.3M |
| 2022-02-08 | PARMAR KUSH | Director | Sell | 140K | $13.05 | $1.8M | 2.6M |
| 2022-02-08 | 5AM Ventures V, L.P. | TenPercentOwner | Sell | 70K | $13.05 | $920K | 1.3M |
| 2022-02-08 | 5AM Ventures V, L.P. | TenPercentOwner | Sell | 140K | $13.05 | $1.8M | 2.6M |
| 2022-01-19 | Fryer Jeffrey M | See Remarks | Buy | 1K | $8.70 | $12K | 44K |
| 2022-01-13 | Uden Stephen | See Remarks | Buy | 4K | $9.06 | $38K | 718K |
| 2022-01-13 | Uden Stephen | See Remarks | Buy | 807 | $9.62 | $8K | 719K |
| 2022-01-12 | Uden Stephen | See Remarks | Buy | 5K | $10.55 | $53K | 714K |
| 2022-01-11 | MACKAY MARTIN | Chief Executive Officer | Buy | 4K | $10.65 | $48K | 283K |
| 2022-01-10 | MACKAY MARTIN | Chief Executive Officer | Buy | 6K | $10.10 | $56K | 278K |
| 2022-01-07 | Fryer Jeffrey M | See Remarks | Buy | 705 | $8.97 | $6K | 33K |
| 2022-01-07 | Fryer Jeffrey M | See Remarks | Buy | 9K | $9.44 | $88K | 43K |
| 2021-08-02 | HUNT RONALD | Director | Buy | 154K | $13.00 | $2.0M | 2.3M |
| 2021-08-02 | FMR LLC | Other | Conversion | 1.7M | price not stated in the filing | not stated | 1.7M |
| 2021-08-02 | SHANNON TIMOTHY M | Director | Buy | 77K | $13.00 | $1000K | 2.4M |
| 2021-08-02 | HUNT RONALD | Director | Buy | 154K | $13.00 | $2.0M | 2.1M |
| 2021-08-02 | Hopfner Robert Lorne | Director | Buy | 577K | $13.00 | $7.5M | 2.3M |
| 2021-08-02 | 5AM Opportunities I, L.P. | TenPercentOwner | Buy | 615K | $13.00 | $8.0M | 1.4M |
| 2021-08-02 | PARMAR KUSH | Director | Buy | 615K | $13.00 | $8.0M | 1.4M |
| 2021-07-29 | Viking Global Opportunities Illiquid Investments Sub-Master LP | TenPercentOwner | Buy | 806K | $13.00 | $10.5M | 4.2M |
| 2021-07-29 | Viking Global Opportunities Illiquid Investments Sub-Master LP | TenPercentOwner | Conversion | 3.4M | price not stated in the filing | not stated | 3.4M |
| 2021-07-28 | Fryer Jeffrey M | See Remarks | Other transaction | 202K | price not stated in the filing | not stated | 202K |
| 2021-07-28 | Fryer Jeffrey M | See Remarks | Other transaction | 202K | price not stated in the filing | not stated | 202K |
| 2021-07-28 | Fryer Jeffrey M | See Remarks | Other transaction | 273K | price not stated in the filing | not stated | 273K |
| 2021-07-28 | Fryer Jeffrey M | See Remarks | Other transaction | 33K | price not stated in the filing | not stated | 33K |
| 2021-07-28 | MACKAY MARTIN | Chief Executive Officer | Other transaction | 273K | price not stated in the filing | not stated | 273K |
| 2021-07-28 | MACKAY MARTIN | Chief Executive Officer | Other transaction | 437K | price not stated in the filing | not stated | 437K |
| 2021-07-28 | Uden Stephen | See Remarks | Other transaction | 709K | price not stated in the filing | not stated | 709K |
| 2021-07-28 | SHANNON TIMOTHY M | Director | Other transaction | 2.3M | price not stated in the filing | not stated | 2.3M |
| 2021-07-28 | HUNT RONALD | Director | Other transaction | 2.0M | price not stated in the filing | not stated | 2.0M |
| 2021-07-28 | Hopfner Robert Lorne | Director | Other transaction | 1.7M | price not stated in the filing | not stated | 1.7M |
| 2021-07-28 | PARMAR KUSH | Director | Other transaction | 791K | price not stated in the filing | not stated | 791K |
| 2021-07-28 | PARMAR KUSH | Director | Other transaction | 2.8M | price not stated in the filing | not stated | 2.8M |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON15 holders report 5% or more of RLYB in their latest filing, 3 on Schedule 13D (active intent). The largest reported stake is Daniel Schneeberger at 17.5% of the class (926,352 shares), filed 2026-06-05 for an event on 2026-05-31.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-08-14 | 13G/Ano. 1 | Bihua Chenparent holding company, individual | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Cormorant Asset Management, LPinvestment adviser, partnership | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Dmitry Balyasnyparent holding company, individual | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | BALYASNY ASSET MANAGEMENT L.P.investment adviser, partnership | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | BAM GP LLCparent holding company, other entity | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Balyasny Asset Management Holdings LPparent holding company, partnership | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Dames GP LLCparent holding company, other entity | 0 | 0.0% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Nantahala Capital Management, LLCinvestment adviser | 188K | 3.6% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Wilmot B. Harkeyparent holding company | 188K | 3.6% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Daniel Mackparent holding company | 188K | 3.6% | 2026-06-30 |
| 2026-08-06 | 13G/Ano. 2 | Abigail P. Johnsonindividual | 795K | 15.0% | 2026-06-30 |
| 2026-08-06 | 13G/Ano. 2 | FMR LLCparent holding company | 795K | 15.0% | 2026-06-30 |
| 2026-08-04 | 13G/Ano. 1 | Laurion Capital Management LPinvestment adviser, partnership | 0 | 0.0% | 2026-06-30 |
| 2026-08-04 | 13G/Ano. 1 | Benjamin Alexander Smithparent holding company, individual | 0 | 0.0% | 2026-06-30 |
| 2026-08-04 | 13G/Ano. 1 | Janaka Sheehan Maduraperumaparent holding company, individual | 0 | 0.0% | 2026-06-30 |
| 2026-06-05 | 13G | Daniel Schneebergerparent holding company, individual | 926K | 17.5% | 2026-05-31 |
| 2026-06-05 | 13G | ADAR1 Capital Management, LLCinvestment adviser, other entity | 926K | 17.5% | 2026-05-31 |
| 2026-05-15 | 13G/Ano. 4 | VIKING GLOBAL INVESTORS LPpartnership | 529K | 10.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 4 | Viking Global Opportunities Parent GP LLCother entity | 529K | 10.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 4 | Viking Global Opportunities GP LLCother entity | 529K | 10.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 4 | Viking Global Opportunities Portfolio GP LLCother entity | 529K | 10.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 4 | Viking Global Opportunities Illiquid Investments Sub-Master LPpartnership | 529K | 10.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 4 | HALVORSEN OLE ANDREASindividual | 529K | 10.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 4 | Shabet Rose Sharonindividual | 529K | 10.0% | 2026-03-31 |
| 2026-05-06 | 13D/Ano. 3 | Scott M. Rocklageindividual | 0 | 0.0% | 2026-05-04 |
| 2026-05-06 | 13D/Ano. 3 | 5AM Ventures V, L.P.partnership | 0 | 0.0% | 2026-05-04 |
| 2026-05-06 | 13D/Ano. 3 | 5AM Partners V, LLCother entity | 0 | 0.0% | 2026-05-04 |
| 2026-05-06 | 13D/Ano. 3 | 5AM Opportunities I, L.P.partnership | 0 | 0.0% | 2026-05-04 |
| 2026-05-06 | 13D/Ano. 3 | 5AM Opportunities I (GP), LLCother entity | 0 | 0.0% | 2026-05-04 |
| 2026-05-06 | 13D/Ano. 3 | Andrew J. Schwabindividual | 0 | 0.0% | 2026-05-04 |
| 2026-05-06 | 13D/Ano. 3 | Kush Parmarindividual | 0 | 0.0% | 2026-05-04 |
| 2026-04-13 | 13G/Ano. 1 | Johnson & Johnsoncorporation | 153K | 2.9% | 2026-03-31 |
| 2026-04-13 | 13G/Ano. 1 | Johnson & Johnson Innovation - JJDC, Inc.corporation | 153K | 2.9% | 2026-03-31 |
| 2026-03-03 | 13D/Ano. 2 | James G. Coulterindividual | 379K | 7.2% | 2026-03-01 |
| 2026-03-03 | 13D/Ano. 2 | TPG GP A, LLCother entity | 379K | 7.2% | 2026-03-01 |
| 2026-03-03 | 13D/Ano. 2 | Jon Winkelriedindividual | 379K | 7.2% | 2026-03-01 |
| 2026-02-17 | 13G/Ano. 3 | Ott David C.individual | 4.2M | 10.0% | 2025-12-31 |
13F holders
Tracked managers holding RLYB at their latest 13F. JSON4 of the 30 tracked managers held RLYB at their latest 13F, $13.0M in total at quarter-end prices. Viking Global Investors is the largest at $8.4M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 3 added shares and 0 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Viking Global Investors | 2026-06-30 | 524K | $8.4M | 0.02% | 0 |
| Renaissance Technologies | 2026-06-30 | 200K | $3.2M | 0.00% | +43K |
| Citadel Advisors | 2026-06-30 | 72K | $1.2M | 0.00% | +52K |
| Two Sigma Investments | 2026-06-30 | 17K | $266K | 0.00% | new |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
What this page is
Rallybio in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows Rallybio (RLYB), SEC CIK 1739410, listed on Nasdaq, classified by the SEC as pharmaceutical preparations. The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-02.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-10-09.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-08-14.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2025-11-06.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-10-29.JSON and CSV
- Company record
- EDGAR filing index for CIK 1739410Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
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Datasets
Frequently Asked Questions
How much of RLYB is sold short?
40,962 shares were held short at the 2026-10-15 settlement, 7.4 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is RLYB's daily short volume?
On 2026-11-02, 16,537 of the 34,363 RLYB shares reported to FINRA were sold short, 48.1% of the day's reported volume. Short volume is a flow for one day, not a position.
Does RLYB have fails to deliver?
The SEC's latest file shows 149 RLYB shares failed to deliver at settlement 2026-10-09. Fails are reported per settlement date and published twice a month with a lag.
Are RLYB insiders buying or selling?
Insiders at RLYB reported 1 open-market sell worth $10K in the last 90 days and no open-market buys. Latest filing: HUNT RONALD (Director) on 2026-10-29.
Who owns 5% or more of RLYB?
15 holders report 5% or more of RLYB in their latest filing, 3 on Schedule 13D (active intent). The largest reported stake is Daniel Schneeberger at 17.5% of the class (926,352 shares), filed 2026-06-05 for an event on 2026-05-31.
Which tracked 13F managers own RLYB?
4 of the 30 tracked 13F managers held RLYB shares at their latest filing, $13.0M in all. The largest: Andreas Halvorsen's Viking Global Investors (524K shares, $8.4M), Renaissance Technologies (200K shares, $3.2M), Ken Griffin's Citadel Advisors (72K shares, $1.2M), Two Sigma Investments (17K shares, $266K).
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.