Altimmune (ALT)
Altimmune 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.
42.2M
Short interest
settlement 2026-10-15
10.4
Days to cover
-0.1 days vs prior
46.7%
Short share of volume
2026-11-02
631
Fails to deliver
settlement 2026-10-14
Thu 5 Nov
Next earnings
estimated date
$44K
Insider flow, 90 days
1 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. JSONAs of 15 October 2026, short interest in ALT is 42,233,791 shares, down 9,515,965 shares over the last month. Over the last 48 readings it ranged from 21,503,786 shares (15 October 2025) to 51,938,259 shares (31 July 2026). At the reported average volume of 4.1M shares a day that is 10.4 days to cover.
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| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 42,233,791 | -8.3% | 4,052,775 | 10.42 |
| 2026-09-30 | 46,079,911 | -11.0% | 4,373,581 | 10.54 |
| 2026-09-15 | 51,749,756 | +4.1% | 3,365,261 | 15.38 |
| 2026-08-31 | 49,714,773 | -2.5% | 4,200,073 | 11.84 |
| 2026-08-14 | 50,972,774 | -1.9% | 4,617,466 | 11.04 |
| 2026-07-31 | 51,938,259 | +7.7% | 4,534,307 | 11.45 |
| 2026-07-15 | 48,242,342 | +1.3% | 3,852,155 | 12.52 |
| 2026-06-30 | 47,634,141 | +13.6% | 5,904,250 | 8.07 |
| 2026-06-15 | 41,927,428 | +7.2% | 2,878,363 | 14.57 |
| 2026-05-29 | 39,121,187 | +3.9% | 2,704,753 | 14.46 |
| 2026-05-15 | 37,637,361 | +6.2% | 3,416,478 | 11.02 |
| 2026-04-30 | 35,446,379 | +23.4% | 7,192,208 | 4.93 |
| 2026-04-15 | 28,734,631 | -1.8% | 2,095,235 | 13.71 |
| 2026-03-31 | 29,248,014 | +10.4% | 3,820,795 | 7.65 |
| 2026-03-13 | 26,485,081 | +3.9% | 3,807,152 | 6.96 |
| 2026-02-27 | 25,499,023 | +1.5% | 2,556,547 | 9.97 |
| 2026-02-13 | 25,131,694 | +4.0% | 3,471,785 | 7.24 |
| 2026-01-30 | 24,163,422 | -8.5% | 6,907,580 | 3.50 |
| 2026-01-15 | 26,407,860 | +2.3% | 6,232,330 | 4.24 |
| 2025-12-31 | 25,810,012 | +8.8% | 5,502,996 | 4.69 |
| 2025-12-15 | 23,718,017 | +2.4% | 3,799,388 | 6.24 |
| 2025-11-28 | 23,157,756 | -0.6% | 3,289,773 | 7.04 |
| 2025-11-14 | 23,285,097 | +6.9% | 3,270,364 | 7.12 |
| 2025-10-31 | 21,780,366 | +1.3% | 2,504,764 | 8.70 |
| 2025-10-15 | 21,503,786 | -17.9% | 2,968,083 | 7.25 |
| 2025-09-30 | 26,194,292 | +4.4% | 3,012,028 | 8.70 |
| 2025-09-15 | 25,084,923 | -6.3% | 1,905,221 | 13.17 |
| 2025-08-29 | 26,765,712 | +5.1% | 3,116,352 | 8.59 |
| 2025-08-15 | 25,460,460 | -1.2% | 2,783,367 | 9.15 |
| 2025-07-31 | 25,760,339 | -8.3% | 3,274,029 | 7.87 |
| 2025-07-15 | 28,097,407 | -9.9% | 6,493,878 | 4.33 |
| 2025-06-30 | 31,181,920 | +27.8% | 16,097,630 | 1.94 |
| 2025-06-13 | 24,400,612 | +11.0% | 4,062,158 | 6.01 |
| 2025-05-30 | 21,981,785 | -3.0% | 2,003,112 | 10.97 |
| 2025-05-15 | 22,671,188 | +0.4% | 2,792,011 | 8.12 |
| 2025-04-30 | 22,577,420 | +0.6% | 1,637,943 | 13.78 |
| 2025-04-15 | 22,441,494 | +2.9% | 2,487,162 | 9.02 |
| 2025-03-31 | 21,815,146 | -2.8% | 2,318,891 | 9.41 |
| 2025-03-14 | 22,452,019 | +3.6% | 3,767,036 | 5.96 |
| 2025-02-28 | 21,665,305 | -3.6% | 2,588,555 | 8.37 |
| 2025-02-14 | 22,472,098 | -3.6% | 1,851,006 | 12.14 |
| 2025-01-31 | 23,319,504 | -5.2% | 1,830,246 | 12.74 |
| 2025-01-15 | 24,593,816 | +3.8% | 2,706,971 | 9.09 |
| 2024-12-31 | 23,693,958 | -0.7% | 2,800,351 | 8.46 |
| 2024-12-13 | 23,854,914 | +1.8% | 3,913,674 | 6.10 |
| 2024-11-29 | 23,434,782 | +2.6% | 2,915,492 | 8.04 |
| 2024-11-15 | 22,836,787 | -0.4% | 5,325,051 | 4.29 |
| 2024-10-31 | 22,936,698 | +3.2% | 1,752,557 | 13.09 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of ALT volume is 46.7%, down 10.3 points over the last five sessions. Over the last 30 readings it ranged from 32.1% (7 October 2026) to 74.2% (5 October 2026). The latest reading is 5.5 points below the 30-session average of 52.1%, on 1.5M shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 683K | 1.5M | 46.7% | 5,188 |
| 2026-10-30 | 1.0M | 2.0M | 51.5% | 45 |
| 2026-10-29 | 650K | 1.3M | 49.8% | 1,668 |
| 2026-10-28 | 1.1M | 2.1M | 56.0% | 1,785 |
| 2026-10-27 | 1.2M | 2.7M | 42.7% | 4,458 |
| 2026-10-26 | 1.1M | 2.0M | 57.0% | 521 |
| 2026-10-23 | 852K | 1.5M | 57.8% | 2,908 |
| 2026-10-22 | 771K | 1.6M | 47.9% | 0 |
| 2026-10-21 | 1.0M | 2.2M | 45.9% | 12,322 |
| 2026-10-20 | 590K | 1.0M | 59.0% | 409 |
| 2026-10-19 | 591K | 1.2M | 51.3% | 1,383 |
| 2026-10-16 | 934K | 1.8M | 53.1% | 302 |
| 2026-10-15 | 778K | 1.7M | 46.7% | 1,136 |
| 2026-10-14 | 1.2M | 2.6M | 46.6% | 4,248 |
| 2026-10-13 | 1.2M | 2.2M | 56.5% | 8,671 |
| 2026-10-12 | 766K | 1.3M | 57.0% | 422 |
| 2026-10-09 | 830K | 1.5M | 53.9% | 3,742 |
| 2026-10-08 | 1.1M | 2.1M | 49.6% | 1,400 |
| 2026-10-07 | 691K | 2.2M | 32.1% | 20,033 |
| 2026-10-06 | 805K | 1.5M | 54.9% | 1,412 |
| 2026-10-05 | 1.4M | 1.9M | 74.2% | 118 |
| 2026-10-02 | 1.4M | 2.2M | 65.0% | 112 |
| 2026-10-01 | 732K | 1.7M | 43.0% | 10,642 |
| 2026-09-30 | 1.1M | 1.9M | 59.5% | 1,045 |
| 2026-09-29 | 880K | 1.6M | 56.0% | 41 |
| 2026-09-28 | 768K | 1.4M | 53.3% | 8 |
| 2026-09-25 | 764K | 1.4M | 53.6% | 3,306 |
| 2026-09-24 | 1.1M | 1.9M | 55.2% | 1,924 |
| 2026-09-23 | 1.3M | 2.5M | 51.5% | 6,592 |
| 2026-09-22 | 686K | 1.9M | 36.5% | 1,165 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 14 October 2026, the fails-to-deliver balance in ALT is 631 shares, down 1,515 shares over the last settlement date. Over the last 30 readings it ranged from 17 shares (3 September 2026) to 147,994 shares (29 June 2026). The latest reading sits at the bottom of that range.
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-14 | 631 | $2.43 | $2K |
| 2026-10-01 | 2,146 | $2.86 | $6K |
| 2026-09-28 | 3,623 | $3.06 | $11K |
| 2026-09-23 | 1,957 | $3.41 | $7K |
| 2026-09-14 | 217 | $3.27 | $710 |
| 2026-09-11 | 1,152 | $3.29 | $4K |
| 2026-09-03 | 17 | $3.28 | $56 |
| 2026-08-24 | 61,991 | $3.11 | $193K |
| 2026-08-12 | 10,537 | $3.00 | $32K |
| 2026-08-06 | 6,228 | $3.03 | $19K |
| 2026-08-04 | 17,013 | $3.00 | $51K |
| 2026-08-03 | 19,165 | $2.84 | $54K |
| 2026-07-31 | 2,773 | $2.98 | $8K |
| 2026-07-16 | 4,669 | $2.98 | $14K |
| 2026-07-01 | 101 | $3.04 | $307 |
| 2026-06-30 | 930 | $2.94 | $3K |
| 2026-06-29 | 147,994 | $2.82 | $417K |
| 2026-06-24 | 1,484 | $2.91 | $4K |
| 2026-06-18 | 138 | $2.64 | $364 |
| 2026-06-05 | 24,917 | $2.92 | $73K |
| 2026-06-02 | 3,569 | $3.01 | $11K |
| 2026-05-26 | 959 | $2.90 | $3K |
| 2026-05-22 | 811 | $2.93 | $2K |
| 2026-05-18 | 114 | $2.85 | $325 |
| 2026-05-08 | 243 | $3.04 | $739 |
| 2026-04-30 | 1,682 | $2.63 | $4K |
| 2026-04-20 | 5,246 | $3.50 | $18K |
| 2026-04-15 | 7,586 | $3.29 | $25K |
| 2026-04-08 | 1,961 | $3.38 | $7K |
| 2026-04-06 | 3,034 | $3.34 | $10K |
Insider trades
SEC Form 4, newest first. JSONInsiders at ALT reported 1 open-market buy worth $44K in the last 90 days and no open-market sells. Latest filing: Arbet-Engels Christophe (Chief Medical Officer) on 2026-10-01.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-10-01 | Arbet-Engels Christophe | Chief Medical Officer | Tax withholding | 13K | $2.76 | $35K | 25K |
| 2026-10-01 | Arbet-Engels Christophe | Chief Medical Officer | Exercise or conversion | 38K | $0.00 | $0 | 38K |
| 2026-10-01 | WEAVER GREGORY L | Chief Financial Officer | Tax withholding | 4K | $2.76 | $12K | 50K |
| 2026-10-01 | WEAVER GREGORY L | Chief Financial Officer | Exercise or conversion | 14K | $0.00 | $0 | 54K |
| 2026-09-16 | Richardson Linda M | Chief Commercial Officer | Tax withholding | 7K | $3.24 | $22K | 17K |
| 2026-09-16 | Richardson Linda M | Chief Commercial Officer | Exercise or conversion | 24K | $0.00 | $0 | 24K |
| 2026-08-13 | Durso Jerome Benedict | President and CEO | Buy | 15K | $2.95 | $44K | 63K |
| 2026-07-31 | Roberts M Scot | Chief Scientific Officer | Grant | 875 | $2.41 | $2K | 114K |
| 2026-07-31 | WEAVER GREGORY L | Chief Financial Officer | Grant | 2K | $2.41 | $4K | 40K |
| 2026-04-06 | GILL JOHN | Director | Buy | 9K | $3.41 | $31K | 22K |
| 2026-04-01 | Durso Jerome Benedict | President and CEO | Buy | 15K | $3.14 | $47K | 48K |
| 2026-04-01 | WEAVER GREGORY L | Chief Financial Officer | Buy | 10K | $3.15 | $31K | 38K |
| 2026-03-06 | Durso Jerome Benedict | President and CEO | Buy | 20K | $3.54 | $71K | 33K |
| 2026-03-06 | WEAVER GREGORY L | Chief Financial Officer | Buy | 5K | $3.54 | $18K | 28K |
| 2026-02-02 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 2K | $5.55 | $13K | 113K |
| 2026-02-02 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 8K | $0.00 | $0 | 115K |
| 2026-01-31 | Jordt Raymond M | Chief Business Officer | Grant | 5K | $3.07 | $14K | 70K |
| 2026-01-31 | Garg Vipin K | Director | Grant | 7K | $3.07 | $21K | 425K |
| 2026-01-31 | Roberts M Scot | Chief Scientific Officer | Grant | 6K | $3.07 | $17K | 107K |
| 2026-01-30 | Garg Vipin K | Director | Tax withholding | 12K | $5.60 | $65K | 418K |
| 2026-01-30 | Garg Vipin K | Director | Exercise or conversion | 27K | $0.00 | $0 | 429K |
| 2026-01-30 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 3K | $5.60 | $16K | 102K |
| 2026-01-30 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 9K | $0.00 | $0 | 105K |
| 2026-01-27 | Jordt Raymond M | Chief Business Officer | Tax withholding | 4K | $6.18 | $26K | 66K |
| 2026-01-27 | Jordt Raymond M | Chief Business Officer | Exercise or conversion | 16K | $0.00 | $0 | 70K |
| 2026-01-27 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 5K | $6.18 | $29K | 95K |
| 2026-01-27 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 16K | $0.00 | $0 | 100K |
| 2026-01-27 | Garg Vipin K | Director | Tax withholding | 18K | $6.18 | $111K | 402K |
| 2026-01-27 | Garg Vipin K | Director | Exercise or conversion | 41K | $0.00 | $0 | 420K |
| 2026-01-25 | Jordt Raymond M | Chief Business Officer | Tax withholding | 4K | $5.50 | $21K | 54K |
| 2026-01-25 | Jordt Raymond M | Chief Business Officer | Exercise or conversion | 15K | $0.00 | $0 | 58K |
| 2026-01-25 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 4K | $5.50 | $24K | 84K |
| 2026-01-25 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 15K | $0.00 | $0 | 89K |
| 2026-01-25 | Garg Vipin K | Director | Tax withholding | 18K | $5.50 | $99K | 379K |
| 2026-01-25 | Garg Vipin K | Director | Exercise or conversion | 42K | $0.00 | $0 | 397K |
| 2026-01-08 | Pisano Wayne | Director | Buy | 5K | $4.08 | $20K | 13K |
| 2026-01-05 | Sohn Catherine A. | Director | Buy | 500 | $4.24 | $2K | 2K |
| 2026-01-01 | Jordt Raymond M | Chief Business Officer | Tax withholding | 2K | $3.61 | $9K | 43K |
| 2026-01-01 | Jordt Raymond M | Chief Business Officer | Exercise or conversion | 9K | $0.00 | $0 | 46K |
| 2025-12-29 | Jorkasky Diane | Director | Buy | 527 | $3.80 | $2K | 527 |
| 2025-12-23 | GILL JOHN | Director | Buy | 13K | $4.10 | $51K | 13K |
| 2025-12-22 | Durso Jerome Benedict | Director | Buy | 13K | $4.13 | $52K | 13K |
| 2025-11-11 | WEAVER GREGORY L | Chief Financial Officer | Tax withholding | 6K | $4.28 | $24K | 23K |
| 2025-11-11 | WEAVER GREGORY L | Chief Financial Officer | Exercise or conversion | 19K | $0.00 | $0 | 29K |
| 2025-07-31 | Jordt Raymond M | Chief Business Officer | Grant | 1K | $3.14 | $4K | 36K |
| 2025-07-31 | Harris Matthew Scott | Chief Medical Officer | Grant | 2K | $3.14 | $6K | 16K |
| 2025-07-31 | Roberts M Scot | Chief Scientific Officer | Grant | 846 | $3.14 | $3K | 74K |
| 2025-03-17 | Sohn Catherine A. | Director | Buy | 1K | $5.78 | $6K | 1K |
| 2025-03-13 | WEAVER GREGORY L | Chief Financial Officer | Buy | 10K | $5.20 | $52K | 10K |
| 2025-03-07 | Harris Matthew Scott | Chief Medical Officer | Gift | 68K | $0.00 | $0 | 14K |
| 2025-02-02 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 8K | $0.00 | $0 | 76K |
| 2025-02-02 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 2K | $6.64 | $15K | 73K |
| 2025-02-02 | Harris Matthew Scott | Chief Medical Officer | Exercise or conversion | 8K | $0.00 | $0 | 85K |
| 2025-02-02 | Harris Matthew Scott | Chief Medical Officer | Tax withholding | 3K | $6.64 | $18K | 82K |
| 2025-02-02 | Garg Vipin K | President and CEO | Exercise or conversion | 19K | $0.00 | $0 | 363K |
| 2025-02-02 | Garg Vipin K | President and CEO | Tax withholding | 8K | $6.64 | $55K | 355K |
| 2025-02-01 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 6K | $0.00 | $0 | 70K |
| 2025-02-01 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 2K | $6.64 | $12K | 68K |
| 2025-02-01 | Harris Matthew Scott | Chief Medical Officer | Tax withholding | 2K | $6.64 | $14K | 77K |
| 2025-02-01 | Harris Matthew Scott | Chief Medical Officer | Exercise or conversion | 6K | $0.00 | $0 | 79K |
| 2025-02-01 | Garg Vipin K | President and CEO | Exercise or conversion | 17K | $0.00 | $0 | 352K |
| 2025-02-01 | Garg Vipin K | President and CEO | Tax withholding | 7K | $6.64 | $48K | 344K |
| 2025-01-31 | Roberts M Scot | Chief Scientific Officer | Grant | 3K | $5.18 | $16K | 63K |
| 2025-01-31 | Jordt Raymond M | Chief Business Officer | Grant | 3K | $5.18 | $14K | 35K |
| 2025-01-31 | Harris Matthew Scott | Chief Medical Officer | Grant | 2K | $5.18 | $10K | 73K |
| 2025-01-31 | Garg Vipin K | President and CEO | Grant | 4K | $5.18 | $21K | 335K |
| 2025-01-30 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 3K | $7.00 | $19K | 60K |
| 2025-01-30 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 9K | $0.00 | $0 | 63K |
| 2025-01-30 | Harris Matthew Scott | Chief Medical Officer | Tax withholding | 3K | $7.00 | $22K | 71K |
| 2025-01-30 | Harris Matthew Scott | Chief Medical Officer | Exercise or conversion | 9K | $0.00 | $0 | 74K |
| 2025-01-30 | Garg Vipin K | President and CEO | Tax withholding | 12K | $7.00 | $82K | 331K |
| 2025-01-30 | Garg Vipin K | President and CEO | Exercise or conversion | 27K | $0.00 | $0 | 343K |
| 2025-01-25 | Garg Vipin K | President and CEO | Exercise or conversion | 42K | $0.00 | $0 | 334K |
| 2025-01-25 | Garg Vipin K | President and CEO | Tax withholding | 18K | $6.98 | $127K | 316K |
| 2025-01-25 | Harris Matthew Scott | Chief Medical Officer | Exercise or conversion | 15K | $0.00 | $0 | 70K |
| 2025-01-25 | Harris Matthew Scott | Chief Medical Officer | Tax withholding | 5K | $6.98 | $35K | 65K |
| 2025-01-25 | Jordt Raymond M | Chief Business Officer | Tax withholding | 4K | $6.98 | $27K | 32K |
| 2025-01-25 | Jordt Raymond M | Chief Business Officer | Exercise or conversion | 15K | $0.00 | $0 | 36K |
| 2025-01-25 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 4K | $6.98 | $30K | 54K |
| 2025-01-25 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 15K | $0.00 | $0 | 58K |
| 2025-01-01 | Jordt Raymond M | Chief Business Officer | Tax withholding | 2K | $7.21 | $18K | 22K |
| 2025-01-01 | Jordt Raymond M | Chief Business Officer | Exercise or conversion | 9K | $0.00 | $0 | 24K |
| 2024-08-19 | Drutz David | Director | Sell | 8K | $6.88 | $56K | 56K |
| 2024-08-19 | Drutz David | Director | Exercise or conversion | 20K | $2.60 | $52K | 50K |
| 2024-08-19 | Drutz David | Director | Sell | 8K | $6.93 | $54K | 42K |
| 2024-08-19 | Drutz David | Director | Exercise or conversion | 22K | $2.50 | $54K | 64K |
| 2024-07-31 | Harris Matthew Scott | Chief Medical Officer | Grant | 1K | $5.41 | $8K | 55K |
| 2024-07-31 | Jordt Raymond M | Chief Business Officer | Grant | 917 | $5.41 | $5K | 15K |
| 2024-07-31 | Roberts M Scot | Chief Scientific Officer | Grant | 650 | $5.41 | $4K | 43K |
| 2024-07-31 | Shutterly Andrew | Acting Chief Financial Officer | Grant | 1K | $5.41 | $7K | 11K |
| 2024-02-02 | Garg Vipin K | President and CEO | Tax withholding | 8K | $9.32 | $78K | 292K |
| 2024-02-02 | Garg Vipin K | President and CEO | Exercise or conversion | 19K | $0.00 | $0 | 300K |
| 2024-02-02 | Harris Matthew Scott | Chief Medical Officer | Tax withholding | 2K | $9.32 | $22K | 54K |
| 2024-02-02 | Harris Matthew Scott | Chief Medical Officer | Exercise or conversion | 8K | $0.00 | $0 | 56K |
| 2024-02-02 | Roberts M Scot | Chief Scientific Officer | Tax withholding | 2K | $9.32 | $22K | 43K |
| 2024-02-02 | Roberts M Scot | Chief Scientific Officer | Exercise or conversion | 8K | $0.00 | $0 | 45K |
| 2024-02-01 | Garg Vipin K | President and CEO | Exercise or conversion | 17K | $0.00 | $0 | 289K |
| 2024-02-01 | Garg Vipin K | President and CEO | Tax withholding | 7K | $9.88 | $72K | 281K |
| 2024-02-01 | Harris Matthew Scott | Chief Medical Officer | Tax withholding | 2K | $9.88 | $18K | 48K |
| 2024-02-01 | Harris Matthew Scott | Chief Medical Officer | Exercise or conversion | 6K | $0.00 | $0 | 50K |
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. JSON17 holders report 5% or more of ALT in their latest filing, all on Schedule 13G (passive). The largest reported stake is David Kroin at 10.0% of the class (19,417,221 shares), filed 2026-04-30 for an event on 2026-04-23.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-05-15 | 13G/Ano. 3 | TANG CAPITAL PARTNERS INTERNATIONAL, LPpartnership | 666K | 0.3% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 3 | KEVIN TANGindividual | 666K | 0.3% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 3 | TANG CAPITAL MANAGEMENT, LLCother entity | 666K | 0.3% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 3 | TANG CAPITAL PARTNERS III, INCcorporation | 0 | 0.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 3 | TANG CAPITAL PARTNERS, LPpartnership | 0 | 0.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 3 | TANG CAPITAL PARTNERS IV, INCcorporation | 0 | 0.0% | 2026-03-31 |
| 2026-05-12 | 13G | STATE STREET CORPORATIONparent holding company | 7.1M | 5.5% | 2026-03-31 |
| 2026-05-01 | 13G | RA Capital Healthcare Fund, L.P.partnership | 13.0M | 6.5% | 2026-04-24 |
| 2026-05-01 | 13G | Rajeev Shahparent holding company, individual | 13.0M | 6.5% | 2026-04-24 |
| 2026-05-01 | 13G | RA Capital Management, L.P.investment adviser, partnership | 13.0M | 6.5% | 2026-04-24 |
| 2026-05-01 | 13G | Peter Kolchinskyparent holding company, individual | 13.0M | 6.5% | 2026-04-24 |
| 2026-05-01 | 13G | Chen Yuindividual | 20.0M | 9.8% | 2026-04-24 |
| 2026-05-01 | 13G | TCG Crossover GP III, LLCother entity | 10.0M | 5.0% | 2026-04-24 |
| 2026-05-01 | 13G | TCG Crossover GP II, LLCother entity | 10.0M | 5.0% | 2026-04-24 |
| 2026-05-01 | 13G | TCG Crossover Fund II, L.P.partnership | 10.0M | 5.0% | 2026-04-24 |
| 2026-05-01 | 13G | TCG Crossover Fund III, L.P.partnership | 10.0M | 5.0% | 2026-04-24 |
| 2026-05-01 | 13G | Shabet Rose Sharonindividual | 13.4M | 6.7% | 2026-04-24 |
| 2026-05-01 | 13G | VIKING GLOBAL INVESTORS LPpartnership | 13.4M | 6.7% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities Parent GP LLCother entity | 13.4M | 6.7% | 2026-04-24 |
| 2026-05-01 | 13G | HALVORSEN OLE ANDREASindividual | 13.4M | 6.7% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities Illiquid Investments Sub-Master LPpartnership | 9.4M | 4.7% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities Portfolio GP LLCother entity | 9.4M | 4.7% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities GP LLCother entity | 9.4M | 4.7% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities Vintage IV (Aggregator) LPpartnership | 4.0M | 2.0% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities Vintage IV Portfolio GP LLCother entity | 4.0M | 2.0% | 2026-04-24 |
| 2026-05-01 | 13G | Viking Global Opportunities Vintage IV GP LLCother entity | 4.0M | 2.0% | 2026-04-24 |
| 2026-04-30 | 13G | David Kroinparent holding company, individual | 19.4M | 10.0% | 2026-04-23 |
| 2026-04-30 | 13G | Deep Track Capital, LPinvestment adviser, other entity | 19.4M | 10.0% | 2026-04-23 |
| 2026-04-30 | 13G | Deep Track Biotechnology Master Fund, Ltd.corporation | 16.8M | 8.7% | 2026-04-23 |
| 2026-04-30 | 13G | Deep Track Special Opportunities Fund, LP.partnership | 2.6M | 1.3% | 2026-04-23 |
| 2026-03-26 | 13G/Ano. 3 | The Vanguard Groupinvestment adviser | 0 | 0.0% | 2026-03-13 |
13F holders
Tracked managers holding ALT at their latest 13F. JSON8 of the 30 tracked managers held ALT at their latest 13F, $46.7M in total at quarter-end prices. Viking Global Investors is the largest at $20.4M (0.1% of its portfolio) as of 2026-06-30. Over the prior quarter 5 added shares and 3 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Viking Global Investors | 2026-06-30 | 6.7M | $20.4M | 0.06% | new |
| Millennium Management | 2026-06-30 | 3.3M | $10.1M | 0.00% | +51K |
| Two Sigma Investments | 2026-06-30 | 2.4M | $7.2M | 0.01% | -98K |
| AQR Capital Management | 2026-06-30 | 1.2M | $3.7M | 0.00% | +1.1M |
| Citadel Advisors | 2026-06-30 | 984K | $3.0M | 0.00% | +535K |
| Point72 Asset Management | 2026-06-30 | 487K | $1.5M | 0.00% | -178K |
| D. E. Shaw & Co. | 2026-06-30 | 202K | $613K | 0.00% | -525K |
| Renaissance Technologies | 2026-06-30 | 72K | $218K | 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
Altimmune 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 Altimmune (ALT), SEC CIK 1326190, 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 2026-10-14.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 2026-05-15.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 2026-08-12.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 2026-10-01.JSON and CSV
- Company record
- EDGAR filing index for CIK 1326190Ticker, 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 companies the SEC classifies as pharmaceutical preparations
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- SWKStanley Black & Decker
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- SYFSynchrony Financial
- SYKStryker
- SYNASynaptics
Datasets
Frequently Asked Questions
How much of ALT is sold short?
42,233,791 shares were held short at the 2026-10-15 settlement, 10.4 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 ALT's daily short volume?
On 2026-11-02, 683,468 of the 1,465,069 ALT shares reported to FINRA were sold short, 46.7% of the day's reported volume. Short volume is a flow for one day, not a position.
Does ALT have fails to deliver?
The SEC's latest file shows 631 ALT shares failed to deliver at settlement 2026-10-14. Fails are reported per settlement date and published twice a month with a lag.
Are ALT insiders buying or selling?
Insiders at ALT reported 1 open-market buy worth $44K in the last 90 days and no open-market sells. Latest filing: Arbet-Engels Christophe (Chief Medical Officer) on 2026-10-01.
Who owns 5% or more of ALT?
17 holders report 5% or more of ALT in their latest filing, all on Schedule 13G (passive). The largest reported stake is David Kroin at 10.0% of the class (19,417,221 shares), filed 2026-04-30 for an event on 2026-04-23.
Which tracked 13F managers own ALT?
8 of the 30 tracked 13F managers held ALT shares at their latest filing, $46.7M in all. The largest: Andreas Halvorsen's Viking Global Investors (6.7M shares, $20.4M), Izzy Englander's Millennium Management (3.3M shares, $10.1M), Two Sigma Investments (2.4M shares, $7.2M), Cliff Asness's AQR Capital Management (1.2M shares, $3.7M), Ken Griffin's Citadel Advisors (984K shares, $3.0M), Steve Cohen's Point72 Asset Management (487K shares, $1.5M). The table above lists all 8.
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.