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aTYR PHARMA (ATYR)

aTYR PHARMA on one page: short interest, daily short volume, fails to deliver, large holders, 13F holders, earnings dates and insider trades. Listed on Nasdaq.

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10.3M

Short interest

settlement 2026-10-15

5.4

Days to cover

+4.4 days vs prior

58.1%

Short share of volume

2026-11-02

3,500

Fails to deliver

settlement 2026-10-09

Thu 5 Nov

Next earnings

estimated date

$0

Insider flow, 90 days

0 buys, 0 sells

As of 2026-11-02.

Short interest

FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSON

As of 15 October 2026, short interest in ATYR is 10,273,700 shares, down 394,457 shares over the last month. Over the last 48 readings it ranged from 1,662,000 shares (31 October 2024) to 37,932,369 shares (30 September 2025). At the reported average volume of 1.9M shares a day that is 5.4 days to cover.

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SettlementShares shortChangeAvg daily volumeDays to cover
2026-10-1510,273,700-20.3%1,905,5175.39
2026-09-3012,893,008+20.9%13,422,3831.00
2026-09-1510,668,157+15.0%896,22911.90
2026-08-319,279,033-1.7%577,42116.07
2026-08-149,441,402-2.9%641,23214.72
2026-07-319,726,056+17.5%826,98811.76
2026-07-158,277,406-42.9%1,945,4524.25
2026-06-3014,505,076-21.6%2,861,0165.07
2026-06-1518,511,717-8.3%1,897,4279.76
2026-05-2920,188,406-5.6%4,028,8845.01
2026-05-1521,394,161+7.8%4,773,9844.48
2026-04-3019,845,053-0.2%785,08625.28
2026-04-1519,884,135+1.4%939,87721.16
2026-03-3119,617,163+3.4%1,001,20419.59
2026-03-1318,967,502+0.9%1,174,24116.15
2026-02-2718,802,360-5.4%1,620,45711.60
2026-02-1319,877,366-2.7%2,359,7318.42
2026-01-3020,432,971-4.2%2,646,9357.72
2026-01-1521,334,051-14.7%1,505,42714.17
2025-12-3125,013,857-17.7%2,246,75111.13
2025-12-1530,385,566+2.0%1,963,71115.47
2025-11-2829,801,092-0.2%3,224,2349.24
2025-11-1429,864,642-3.9%3,920,1747.62
2025-10-3131,060,738-14.1%5,105,9556.08
2025-10-1536,142,593-4.7%10,668,9753.39
2025-09-3037,932,369+14.6%21,114,0481.80
2025-09-1533,089,093+12.5%20,997,8021.58
2025-08-2929,405,110+4.1%3,659,5468.04
2025-08-1528,245,132+10.3%3,937,4687.17
2025-07-3125,598,382+25.6%7,486,1083.42
2025-07-1520,381,870+10.4%3,502,8065.82
2025-06-3018,464,705+35.3%4,194,3074.40
2025-06-1313,644,953-0.9%2,936,7224.65
2025-05-3013,770,149+8.6%1,670,3748.24
2025-05-1512,681,301+8.5%1,217,45110.42
2025-04-3011,691,227+16.6%1,066,76710.96
2025-04-1510,025,170+20.5%1,509,7916.64
2025-03-318,322,026+20.3%1,310,3316.35
2025-03-146,920,509+31.6%2,092,4183.31
2025-02-285,259,028+20.8%2,041,8722.58
2025-02-144,354,940+14.1%818,3915.32
2025-01-313,816,730+8.6%641,7495.95
2025-01-153,515,857-3.6%990,0673.55
2024-12-313,647,026+24.9%958,7723.80
2024-12-132,920,070+34.3%674,7494.33
2024-11-292,173,825+2.8%793,0262.74
2024-11-152,114,376+27.2%806,0692.62
2024-10-311,662,000+56.0%1,345,2881.24

Daily short volume

FINRA Reg SHO, the last 30 sessions. JSON

As of 2 November 2026, the short share of ATYR volume is 58.1%, up 1.6 points over the last five sessions. Over the last 30 readings it ranged from 31.0% (13 October 2026) to 66.6% (27 October 2026). The latest reading is 9.1 points above the 30-session average of 49.0%, on 222K shares reported.

DateShort volumeTotal volumeShort shareExempt
2026-11-02129K222K58.1%18,171
2026-10-3040K76K52.5%2,548
2026-10-2977K151K51.0%36
2026-10-281.2M1.9M61.7%68,451
2026-10-273.2M4.8M66.6%513,817
2026-10-261.1M1.9M56.5%103,637
2026-10-23302K818K36.9%0
2026-10-22227K618K36.7%14,400
2026-10-21218K550K39.6%0
2026-10-20367K846K43.3%208
2026-10-19699K1.3M53.5%0
2026-10-16392K1.0M38.2%0
2026-10-15430K1.2M36.4%36,249
2026-10-14614K1.5M42.1%20,587
2026-10-13507K1.6M31.0%81,969
2026-10-12630K1.4M44.6%78,614
2026-10-09432K721K59.9%26,186
2026-10-08440K1.1M38.7%21,859
2026-10-07280K569K49.1%0
2026-10-06273K614K44.5%200
2026-10-05384K931K41.3%0
2026-10-02681K1.2M56.7%35,527
2026-10-01705K1.2M57.5%22,740
2026-09-30670K1.2M55.3%114,672
2026-09-291.2M2.3M51.7%44,672
2026-09-281.1M2.3M49.2%136,312
2026-09-252.0M3.6M54.2%284,545
2026-09-248.9M16.9M52.8%324,273
2026-09-23432K711K60.8%37,159
2026-09-22390K773K50.4%3,609

Fails to deliver

SEC, the last 30 settlement dates with a fail. JSON

As of 9 October 2026, the fails-to-deliver balance in ATYR is 3,500 shares, down 1,305 shares over the last settlement date. Over the last 30 readings it ranged from 19 shares (6 October 2026) to 82,298 shares (27 July 2026). The latest reading sits at the bottom of that range.

SettlementShares failedPriceValue
2026-10-093,500$0.26$910
2026-10-084,805$0.28$1K
2026-10-07484$0.28$136
2026-10-0619$0.29$6
2026-10-05406$0.29$118
2026-10-01284$0.30$85
2026-09-304,097$0.31$1K
2026-09-23406$0.36$146
2026-09-1813,043$0.38$5K
2026-09-09327$0.48$157
2026-09-08156$0.50$78
2026-09-042,614$0.50$1K
2026-08-2637$0.57$21
2026-08-252,701$0.53$1K
2026-08-216,993$0.50$3K
2026-08-20128$0.53$68
2026-08-181,261$0.52$656
2026-08-171,261$0.56$706
2026-08-1110,853$0.53$6K
2026-08-0568$0.53$36
2026-08-0488$0.49$43
2026-08-0389$0.49$44
2026-07-282,714$0.49$1K
2026-07-2782,298$0.47$39K
2026-07-24412$0.50$206
2026-07-1712,692$0.52$7K
2026-07-145,800$0.50$3K
2026-07-107,386$0.58$4K
2026-07-0930,830$0.64$20K
2026-07-0859,173$0.61$36K

Insider trades

SEC Form 4, newest first. JSON

No open-market insider trades were reported for ATYR in the last 90 days. The most recent filings are listed below. Latest filing: SCHIMMEL PAUL (Director) on 2026-05-27.

DateInsiderTitleTypeSharesPriceValueOwned after
2026-05-27SCHIMMEL PAULDirectorBuy100K$0.50$50K779K
2026-02-04DENYES NANCYGeneral CounselSell1K$0.98$1K33K
2026-02-04Broadfoot Jill MarieChief Financial OfficerSell2K$0.98$2K37K
2026-02-04Shukla SanjayPresident and CEOSell4K$0.98$4K154K
2026-02-03DENYES NANCYGeneral CounselExercise or conversion3Kprice not stated in the filingnot stated34K
2026-02-03Broadfoot Jill MarieChief Financial OfficerExercise or conversion4Kprice not stated in the filingnot stated39K
2026-02-03Shukla SanjayPresident and CEOExercise or conversion10Kprice not stated in the filingnot stated157K
2025-10-09SCHIMMEL PAULDirectorBuy318K$0.94$299K1.4M
2025-10-08SCHIMMEL PAULDirectorBuy682K$0.90$612K1.1M
2025-03-17Gross Jane ADirectorBuy4K$4.00$15K10K
2025-02-04DENYES NANCYGeneral CounselSell899$3.78$3K27K
2025-02-04Broadfoot Jill MarieChief Financial OfficerSell1K$3.78$5K32K
2025-02-03DENYES NANCYGeneral CounselExercise or conversion3Kprice not stated in the filingnot stated27K
2025-02-03Broadfoot Jill MarieChief Financial OfficerExercise or conversion4Kprice not stated in the filingnot stated33K
2025-02-03Shukla SanjayPresident and CEOExercise or conversion10Kprice not stated in the filingnot stated147K
2024-07-24SCHIMMEL PAULDirectorBuy52K$1.93$101K413K
2024-07-23SCHIMMEL PAULDirectorBuy7K$1.82$12K361K
2024-07-22SCHIMMEL PAULDirectorBuy41K$1.74$71K354K
2024-06-05DENYES NANCYGeneral CounselBuy5K$1.86$9K22K

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. JSON

5 holders report 5% or more of ATYR in their latest filing, all on Schedule 13G (passive). The largest reported stake is J. Christopher Donahue at 5.1% of the class (4,965,414 shares), filed 2026-10-07 for an event on 2026-09-30.

FiledFormHolderSharesOf classEvent
2026-10-0713G/Ano. 12J. Christopher Donahueindividual5.0M5.1%2026-09-30
2026-10-0713G/Ano. 12Ann C. Donahueindividual5.0M5.1%2026-09-30
2026-10-0713G/Ano. 12Thomas R. Donahueindividual5.0M5.1%2026-09-30
2026-10-0713G/Ano. 12Voting Shares Irrevocable Trustother entity5.0M5.1%2026-09-30
2026-10-0713G/Ano. 12Federated Hermes, Inc.parent holding company5.0M5.1%2026-09-30
2026-08-0613G/Ano. 15FMR LLCparent holding company2.5M2.5%2026-06-30
2026-08-0613G/Ano. 15Abigail P. Johnsonindividual2.5M2.5%2026-06-30
2026-07-2713G/Ano. 1BlackRock, Inc.parent holding company1.7M1.8%2026-06-30
2026-03-2613G/Ano. 1The Vanguard Groupinvestment adviser00.0%2026-03-13

13F holders

Tracked managers holding ATYR at their latest 13F. JSON

6 of the 30 tracked managers held ATYR at their latest 13F, $3.6M in total at quarter-end prices. AQR Capital Management is the largest at $1.6M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 5 added shares and 1 cut.

FundQuarterSharesValueOf portfolioChange in shares
AQR Capital Management2026-06-302.6M$1.6M0.00%+2.1M
Two Sigma Investments2026-06-301.2M$743K0.00%+101K
Citadel Advisors2026-06-301.2M$741K0.00%+1.2M
Millennium Management2026-06-30656K$392K0.00%-985K
Renaissance Technologies2026-06-30165K$99K0.00%+125K
Point72 Asset Management2026-06-3037K$22K0.00%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

aTYR PHARMA 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 aTYR PHARMA (ATYR), SEC CIK 1339970, listed on Nasdaq. 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 2026-10-07.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 2026-05-15.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 2026-05-27.JSON and CSV
Company record
EDGAR filing index for CIK 1339970Ticker, 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.

Other company pages

Datasets

Frequently Asked Questions

How much of ATYR is sold short?
10,273,700 shares were held short at the 2026-10-15 settlement, 5.4 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 ATYR's daily short volume?
On 2026-11-02, 128,913 of the 221,948 ATYR shares reported to FINRA were sold short, 58.1% of the day's reported volume. Short volume is a flow for one day, not a position.
Does ATYR have fails to deliver?
The SEC's latest file shows 3,500 ATYR shares failed to deliver at settlement 2026-10-09. Fails are reported per settlement date and published twice a month with a lag.
Are ATYR insiders buying or selling?
No open-market insider trades were reported for ATYR in the last 90 days. The most recent filings are listed below. Latest filing: SCHIMMEL PAUL (Director) on 2026-05-27.
Who owns 5% or more of ATYR?
5 holders report 5% or more of ATYR in their latest filing, all on Schedule 13G (passive). The largest reported stake is J. Christopher Donahue at 5.1% of the class (4,965,414 shares), filed 2026-10-07 for an event on 2026-09-30.
Which tracked 13F managers own ATYR?
6 of the 30 tracked 13F managers held ATYR shares at their latest filing, $3.6M in all. The largest: Cliff Asness's AQR Capital Management (2.6M shares, $1.6M), Two Sigma Investments (1.2M shares, $743K), Ken Griffin's Citadel Advisors (1.2M shares, $741K), Izzy Englander's Millennium Management (656K shares, $392K), Renaissance Technologies (165K shares, $99K), Steve Cohen's Point72 Asset Management (37K shares, $22K).

Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.