ACELYRIN, Inc.
SLRNDelisted May 21, 2025- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001962918
ACELYRIN, Inc. was delisted on May 21, 2025; its insiders filed their last Form 4 on May 23, 2025; 106 institutions reported holding it in 13F filings for Q1 2025, worth $182.6M in total; no superinvestor held it.
Four kinds of short-selling data, each measuring something different:
- Short interest: shares sold short and not yet bought back, as of a settlement date. FINRA publishes it twice a month, about eight business days after the settlement date.
- Daily short volume: shares sold short each day in off-exchange trades reported to FINRA. It counts trades, not open positions, and is published the next day.
- Fails-to-deliver: shares not delivered by the settlement date. The SEC publishes them twice a month, about two weeks late.
- ATS (dark pool) volume: weekly volume on alternative trading systems and other off-exchange venues. FINRA publishes it two to four weeks after the week.
More in the glossary.
Short interest
Shares sold short and not yet bought back, from FINRA, on every settlement date in the last two years.
- Short interest
- 4.24M
- Shares, settlement May 15, 2025
- Change
- +674.9K
- +18.9% vs. Apr 30, 2025
- Days to cover
- 3.86
- Short interest ÷ average daily volume
- Average daily volume
- 1.10M
- Shares, as reported by FINRA
| Settlement date | Short interest | Change | Change % | Avg. daily volume | Days to cover |
|---|---|---|---|---|---|
| May 15, 2025 | 4.24M | +674.9K | +18.9% | 1.10M | 3.86 |
| Apr 30, 2025 | 3.57M | −123.6K | −3.4% | 623.7K | 5.72 |
| Apr 15, 2025 | 3.69M | +43.1K | +1.2% | 1.14M | 3.24 |
| Mar 31, 2025 | 3.65M | −1.04M | −22.1% | 768.9K | 4.75 |
| Mar 14, 2025 | 4.68M | +382.4K | +8.9% | 1.45M | 3.22 |
| Feb 28, 2025 | 4.30M | −414.0K | −8.8% | 3.85M | 1.12 |
| Feb 14, 2025 | 4.72M | −1.15M | −19.6% | 3.85M | 1.23 |
| Jan 31, 2025 | 5.87M | −658.2K | −10.1% | 942.3K | 6.23 |
| Jan 15, 2025 | 6.53M | +385.1K | +6.3% | 2.70M | 2.42 |
| Dec 31, 2024 | 6.14M | +151.8K | +2.5% | 638.5K | 9.62 |
| Dec 13, 2024 | 5.99M | +270.9K | +4.7% | 921.0K | 6.50 |
| Nov 29, 2024 | 5.72M | −15.0K | −0.3% | 432.7K | 13.22 |
| Nov 15, 2024 | 5.73M | +1.03M | +22.0% | 488.7K | 11.73 |
| Oct 31, 2024 | 4.70M | −460.4K | −8.9% | 638.9K | 7.36 |
| Oct 15, 2024 | 5.16M | −1.23M | −19.2% | 539.1K | 9.57 |
| Sep 30, 2024 | 6.39M | +296.0K | +4.9% | 1.20M | 5.32 |
| Sep 13, 2024 | 6.09M | −1.10M | −15.3% | 654.2K | 9.32 |
| Aug 30, 2024 | 7.20M | +263.9K | +3.8% | 921.6K | 7.81 |
| Aug 15, 2024 | 6.93M | −288.1K | −4.0% | 1.59M | 4.36 |
| Jul 31, 2024 | 7.22M | +411.5K | +6.0% | 1.33M | 5.44 |
| Jul 15, 2024 | 6.81M | −277.6K | −3.9% | 842.9K | 8.08 |
| Jun 28, 2024 | 7.09M | +103.1K | +1.5% | 1.11M | 6.39 |
| Jun 14, 2024 | 6.98M | +133.3K | +2.0% | 610.4K | 11.44 |
| May 31, 2024 | 6.85M | −176.0K | −2.5% | 998.6K | 6.86 |
| May 15, 2024 | 7.02M | −1.50M | −17.6% | 862.6K | 8.14 |
| Apr 30, 2024 | 8.53M | +680.6K | +8.7% | 1.05M | 8.15 |
| Apr 15, 2024 | 7.85M | −102.9K | −1.3% | 893.3K | 8.78 |
| Mar 28, 2024 | 7.95M | −463.2K | −5.5% | 1.78M | 4.46 |
| Mar 15, 2024 | 8.41M | +1.48M | +21.4% | 1.59M | 5.28 |
| Feb 29, 2024 | 6.93M | +233.9K | +3.5% | 1.27M | 5.45 |
| Feb 15, 2024 | 6.69M | +248.1K | +3.9% | 881.3K | 7.59 |
| Jan 31, 2024 | 6.45M | +308.9K | +5.0% | 1.34M | 4.82 |
| Jan 12, 2024 | 6.14M | −632.3K | −9.3% | 653.4K | 9.39 |
| Dec 29, 2023 | 6.77M | −507.5K | −7.0% | 925.7K | 7.31 |
| Dec 15, 2023 | 7.28M | +600.6K | +9.0% | 1.42M | 5.11 |
| Nov 30, 2023 | 6.68M | +424.0K | +6.8% | 1.54M | 4.34 |
| Nov 15, 2023 | 6.25M | −1.98M | −24.0% | 1.28M | 4.87 |
| Oct 31, 2023 | 8.23M | −478.8K | −5.5% | 614.3K | 13.39 |
| Oct 13, 2023 | 8.71M | +24.2K | +0.3% | 744.3K | 11.70 |
| Sep 29, 2023 | 8.68M | +2.57M | +42.0% | 1.15M | 7.53 |
| Sep 15, 2023 | 6.11M | −231.3K | −3.7% | 3.38M | 1.81 |
| Aug 31, 2023 | 6.34M | +871.2K | +15.9% | 855.9K | 7.41 |
| Aug 15, 2023 | 5.47M | −426.5K | −7.2% | 915.0K | 5.98 |
| Jul 31, 2023 | 5.90M | −213.0K | −3.5% | 482.3K | 12.23 |
| Jul 14, 2023 | 6.11M | −140.2K | −2.2% | 407.9K | 14.98 |
| Jun 30, 2023 | 6.25M | +2.95M | +89.4% | 1.47M | 4.25 |
| Jun 15, 2023 | 3.30M | +884.7K | +36.6% | 383.6K | 8.61 |
| May 31, 2023 | 2.42M | +679.2K | +39.1% | 442.3K | 5.47 |
| May 15, 2023 | 1.74M | +1.74M | +100.0% | 1.45M | 1.20 |
Fails-to-deliver
Shares that weren't delivered by the settlement date, from the SEC, for the last 30 dates with fails. The price is the previous day's closing price published by the SEC.
| Settlement date | Shares | Price | Value |
|---|---|---|---|
| May 20, 2025 | 47,743 | $2.23 | $106.5K |
| May 19, 2025 | 3,873 | $2.25 | $8.71K |
| May 14, 2025 | 3,064 | $2.09 | $6.40K |
| May 13, 2025 | 6,242 | $2.48 | $15.5K |
| May 12, 2025 | 26,403 | $2.36 | $62.3K |
| May 8, 2025 | 6,512 | $2.42 | $15.8K |
| May 6, 2025 | 6,411 | $2.54 | $16.3K |
| May 1, 2025 | 822 | $2.47 | $2.03K |
| Apr 30, 2025 | 267 | $2.45 | $654.15 |
| Apr 29, 2025 | 2,387 | $2.18 | $5.20K |
| Apr 28, 2025 | 3,651 | $2.17 | $7.92K |
| Apr 25, 2025 | 52,036 | $2.17 | $112.9K |
| Apr 24, 2025 | 393 | $2.25 | $884.25 |
| Apr 22, 2025 | 227 | $2.28 | $517.56 |
| Apr 21, 2025 | 6,299 | $2.20 | $13.9K |
| Apr 17, 2025 | 18,349 | $2.20 | $40.4K |
| Apr 16, 2025 | 16,135 | $2.23 | $36.0K |
| Apr 14, 2025 | 2,617 | $2.23 | $5.84K |
| Apr 11, 2025 | 2,614 | $2.15 | $5.62K |
| Apr 10, 2025 | 19,583 | $2.18 | $42.7K |
| Apr 9, 2025 | 4,836 | $2.08 | $10.1K |
| Apr 2, 2025 | 9,043 | $2.51 | $22.7K |
| Apr 1, 2025 | 138 | $2.47 | $340.86 |
| Mar 31, 2025 | 3,922 | $2.60 | $10.2K |
| Mar 28, 2025 | 1,268 | $2.64 | $3.35K |
| Mar 27, 2025 | 489 | $2.54 | $1.24K |
| Mar 25, 2025 | 212 | $2.64 | $559.68 |
| Mar 24, 2025 | 734 | $2.75 | $2.02K |
| Mar 21, 2025 | 89,818 | $2.77 | $248.8K |
| Mar 20, 2025 | 696 | $2.79 | $1.94K |
Daily short volume
Off-exchange short-sale volume, not short interest: shares sold short each day in trades reported to FINRA, for the last 30 trading days.
The short volume ratio isn't a sentiment gauge: market makers sell short to fill buy orders and to hedge, so short sales are usually about half of off-exchange volume.
| Trade date | Short volume | Short exempt | Off-exchange volume | Short volume ratio |
|---|---|---|---|---|
| May 20, 2025 | 291,590 | 2,050 | 1,343,059 | 21.7% |
| May 19, 2025 | 151,937 | 500 | 647,734 | 23.5% |
| May 16, 2025 | 126,367 | 0 | 528,695 | 23.9% |
| May 15, 2025 | 275,291 | 0 | 898,212 | 30.6% |
| May 14, 2025 | 163,026 | 2,126 | 508,179 | 32.1% |
| May 13, 2025 | 396,812 | 6,102 | 754,001 | 52.6% |
| May 12, 2025 | 83,950 | 0 | 286,361 | 29.3% |
| May 9, 2025 | 54,045 | 0 | 181,143 | 29.8% |
| May 8, 2025 | 103,959 | 6,302 | 248,308 | 41.9% |
| May 7, 2025 | 150,043 | 0 | 280,738 | 53.4% |
| May 6, 2025 | 251,627 | 0 | 294,712 | 85.4% |
| May 5, 2025 | 201,437 | 0 | 254,609 | 79.1% |
| May 2, 2025 | 85,383 | 0 | 209,109 | 40.8% |
| May 1, 2025 | 439,560 | 1,804 | 1,700,811 | 25.8% |
| Apr 30, 2025 | 38,958 | 0 | 120,186 | 32.4% |
| Apr 29, 2025 | 181,570 | 0 | 333,122 | 54.5% |
| Apr 28, 2025 | 80,702 | 0 | 112,664 | 71.6% |
| Apr 25, 2025 | 64,032 | 0 | 285,765 | 22.4% |
| Apr 24, 2025 | 177,389 | 0 | 263,942 | 67.2% |
| Apr 23, 2025 | 50,149 | 0 | 159,408 | 31.5% |
| Apr 22, 2025 | 56,748 | 0 | 595,144 | 9.5% |
| Apr 21, 2025 | 119,112 | 48 | 870,843 | 13.7% |
| Apr 17, 2025 | 28,582 | 204 | 387,209 | 7.4% |
| Apr 16, 2025 | 104,779 | 0 | 249,946 | 41.9% |
| Apr 15, 2025 | 94,488 | 0 | 262,129 | 36.0% |
| Apr 14, 2025 | 74,673 | 0 | 213,760 | 34.9% |
| Apr 11, 2025 | 106,499 | 0 | 263,779 | 40.4% |
| Apr 10, 2025 | 247,389 | 461 | 465,072 | 53.2% |
| Apr 9, 2025 | 66,930 | 1,920 | 205,553 | 32.6% |
| Apr 8, 2025 | 268,096 | 8 | 588,783 | 45.5% |
ATS (dark pool) volume
Weekly volume on alternative trading systems (ATS) and other off-exchange (OTC) venues, from FINRA, for the last 12 weeks. ATS share is ATS volume ÷ (ATS + OTC volume), not a share of all trading.
| Week of | Tier | ATS shares | ATS trades | Other OTC shares | Other OTC trades | ATS share |
|---|---|---|---|---|---|---|
| May 19, 2025 | T2 | 1,111,925 | 7,602 | 898,146 | 1,441 | 55.3% |
| May 12, 2025 | T2 | 1,526,482 | 13,565 | 1,469,008 | 2,819 | 51.0% |
| May 5, 2025 | T2 | 464,210 | 5,724 | 824,772 | 1,348 | 36.0% |
| Apr 28, 2025 | T2 | 667,868 | 5,656 | 1,830,596 | 1,355 | 26.7% |
| Apr 21, 2025 | T2 | 1,630,960 | 4,568 | 571,029 | 1,423 | 74.1% |
| Apr 14, 2025 | T2 | 842,911 | 4,598 | 288,929 | 1,273 | 74.5% |
| Apr 7, 2025 | T2 | 1,293,147 | 7,654 | 850,754 | 1,760 | 60.3% |
| Mar 31, 2025 | T2 | 1,286,633 | 9,855 | 2,644,309 | 3,392 | 32.7% |
| Mar 24, 2025 | T2 | 650,665 | 5,884 | 394,683 | 1,536 | 62.2% |
| Mar 17, 2025 | T2 | 1,252,036 | 6,495 | 611,329 | 1,788 | 67.2% |
| Mar 10, 2025 | T2 | 1,589,426 | 8,978 | 727,067 | 2,446 | 68.6% |
| Mar 3, 2025 | T2 | 3,316,044 | 10,283 | 1,547,116 | 4,192 | 68.2% |