Seres Therapeutics (MCRB)
Seres Therapeutics on one page: short interest, daily short volume, fails to deliver, planned sales, 13F holders, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as pharmaceutical preparations.
312K
Short interest
settlement 2026-10-15
3.5
Days to cover
-1.7 days vs prior
63.8%
Short share of volume
2026-11-02
10,817
Fails to deliver
settlement 2026-10-02
Wed 4 Nov
Next earnings
estimated date
-$2K
Insider flow, 90 days
0 buys, 4 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 MCRB is 312,339 shares, up 10,995 shares over the last month. Over the last 48 readings it ranged from 157,327 shares (30 June 2026) to 20,440,169 shares (31 December 2024). The latest reading sits at the bottom of that range. At the reported average volume of 91K shares a day that is 3.5 days to cover.
Embed this chart.The embed keeps its attribution line.
<iframe src="https://xoomar.com/embed/stocks/mcrb" 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 | 312,339 | -0.6% | 90,602 | 3.45 |
| 2026-09-30 | 314,264 | +4.3% | 61,066 | 5.15 |
| 2026-09-15 | 301,344 | -15.5% | 52,639 | 5.72 |
| 2026-08-31 | 356,541 | -3.1% | 58,386 | 6.11 |
| 2026-08-14 | 367,864 | +16.9% | 67,863 | 5.42 |
| 2026-07-31 | 314,545 | +3.7% | 53,094 | 5.92 |
| 2026-07-15 | 303,423 | +92.9% | 151,675 | 2.00 |
| 2026-06-30 | 157,327 | -28.4% | 118,979 | 1.32 |
| 2026-06-15 | 219,815 | -54.1% | 102,140 | 2.15 |
| 2026-05-29 | 478,817 | -6.6% | 30,846 | 15.52 |
| 2026-05-15 | 512,802 | -5.2% | 46,263 | 11.08 |
| 2026-04-30 | 540,750 | -7.6% | 61,501 | 8.79 |
| 2026-04-15 | 585,069 | -2.0% | 39,306 | 14.88 |
| 2026-03-31 | 597,314 | -5.0% | 49,521 | 12.06 |
| 2026-03-13 | 628,417 | -4.1% | 43,943 | 14.30 |
| 2026-02-27 | 655,113 | -15.4% | 58,265 | 11.24 |
| 2026-02-13 | 774,647 | -6.3% | 153,726 | 5.04 |
| 2026-01-30 | 826,932 | -5.5% | 37,362 | 22.13 |
| 2026-01-15 | 874,572 | -2.8% | 46,709 | 18.72 |
| 2025-12-31 | 900,095 | -9.1% | 68,080 | 13.22 |
| 2025-12-15 | 989,990 | -0.7% | 91,220 | 10.85 |
| 2025-11-28 | 996,857 | +7.7% | 604,813 | 1.65 |
| 2025-11-14 | 925,479 | -6.0% | 96,640 | 9.58 |
| 2025-10-31 | 984,687 | +23.3% | 85,619 | 11.50 |
| 2025-10-15 | 798,666 | -7.0% | 117,013 | 6.83 |
| 2025-09-30 | 858,372 | -8.3% | 139,760 | 6.14 |
| 2025-09-15 | 936,245 | -7.5% | 378,634 | 2.47 |
| 2025-08-29 | 1,012,144 | -2.1% | 117,506 | 8.61 |
| 2025-08-15 | 1,034,377 | +3.0% | 122,470 | 8.45 |
| 2025-07-31 | 1,004,423 | +16.6% | 126,313 | 7.95 |
| 2025-07-15 | 861,106 | +24.2% | 175,216 | 4.91 |
| 2025-06-30 | 693,134 | +2.0% | 120,771 | 5.74 |
| 2025-06-13 | 679,397 | -4.5% | 81,335 | 8.35 |
| 2025-05-30 | 711,221 | -11.0% | 69,141 | 10.29 |
| 2025-05-15 | 798,969 | +30.9% | 108,120 | 7.39 |
| 2025-04-30 | 610,359 | -96.0% | 202,886 | 3.01 |
| 2025-04-15 | 15,262,138 | -4.7% | 1,276,585 | 11.96 |
| 2025-03-31 | 16,010,235 | -4.2% | 812,899 | 19.70 |
| 2025-03-14 | 16,718,590 | -3.0% | 908,601 | 18.40 |
| 2025-02-28 | 17,234,746 | -2.6% | 711,413 | 24.23 |
| 2025-02-14 | 17,694,032 | +1.4% | 784,322 | 22.56 |
| 2025-01-31 | 17,456,803 | -13.8% | 2,989,948 | 5.84 |
| 2025-01-15 | 20,261,193 | -0.9% | 1,298,346 | 15.61 |
| 2024-12-31 | 20,440,169 | +4.2% | 1,890,611 | 10.81 |
| 2024-12-13 | 19,613,483 | +12.8% | 3,038,507 | 6.45 |
| 2024-11-29 | 17,381,399 | +7.1% | 4,495,587 | 3.87 |
| 2024-11-15 | 16,235,306 | -9.1% | 2,512,081 | 6.46 |
| 2024-10-31 | 17,852,612 | -1.1% | 1,872,282 | 9.54 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of MCRB volume is 63.8%, up 35.3 points over the last five sessions. Over the last 30 readings it ranged from 28.6% (26 October 2026) to 73.4% (22 October 2026). The latest reading is 12.1 points above the 30-session average of 51.8%, on 22K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 14K | 22K | 63.8% | 634 |
| 2026-10-30 | 27K | 70K | 38.6% | 950 |
| 2026-10-29 | 24K | 44K | 55.1% | 1,925 |
| 2026-10-28 | 15K | 38K | 40.2% | 2,061 |
| 2026-10-27 | 23K | 77K | 30.3% | 1 |
| 2026-10-26 | 6K | 23K | 28.6% | 0 |
| 2026-10-23 | 23K | 32K | 70.0% | 151 |
| 2026-10-22 | 51K | 70K | 73.4% | 14,130 |
| 2026-10-21 | 7K | 18K | 40.9% | 0 |
| 2026-10-20 | 18K | 38K | 46.2% | 0 |
| 2026-10-19 | 3K | 8K | 45.2% | 0 |
| 2026-10-16 | 10K | 15K | 64.8% | 0 |
| 2026-10-15 | 6K | 11K | 59.7% | 0 |
| 2026-10-14 | 4K | 12K | 32.6% | 0 |
| 2026-10-13 | 15K | 23K | 66.5% | 0 |
| 2026-10-12 | 6K | 17K | 32.7% | 0 |
| 2026-10-09 | 28K | 42K | 66.6% | 8,206 |
| 2026-10-08 | 45K | 96K | 46.8% | 4,451 |
| 2026-10-07 | 14K | 28K | 50.3% | 0 |
| 2026-10-06 | 16K | 33K | 49.5% | 0 |
| 2026-10-05 | 14K | 27K | 51.6% | 0 |
| 2026-10-02 | 22K | 54K | 39.9% | 5,294 |
| 2026-10-01 | 63K | 95K | 66.9% | 16,370 |
| 2026-09-30 | 16K | 30K | 52.3% | 0 |
| 2026-09-29 | 17K | 26K | 64.4% | 0 |
| 2026-09-28 | 15K | 30K | 49.9% | 0 |
| 2026-09-25 | 8K | 17K | 46.4% | 0 |
| 2026-09-24 | 21K | 31K | 70.1% | 0 |
| 2026-09-23 | 23K | 33K | 69.9% | 0 |
| 2026-09-22 | 6K | 16K | 40.1% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 2 October 2026, the fails-to-deliver balance in MCRB is 10,817 shares, up 10,614 shares over the last settlement date. Over the last 30 readings it ranged from 1 share (22 April 2026) to 25,000 shares (9 June 2026).
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-02 | 10,817 | $2.93 | $32K |
| 2026-09-22 | 203 | $4.07 | $826 |
| 2026-09-18 | 25 | $4.10 | $103 |
| 2026-09-17 | 11 | $4.21 | $46 |
| 2026-08-26 | 546 | $5.00 | $3K |
| 2026-08-24 | 125 | $4.56 | $570 |
| 2026-08-18 | 1,296 | $4.51 | $6K |
| 2026-08-14 | 394 | $4.48 | $2K |
| 2026-08-10 | 11 | $4.87 | $54 |
| 2026-08-07 | 311 | $4.82 | $1K |
| 2026-08-06 | 823 | $5.01 | $4K |
| 2026-08-05 | 81 | $5.25 | $425 |
| 2026-06-09 | 25,000 | $6.28 | $157K |
| 2026-06-04 | 5,718 | $7.17 | $41K |
| 2026-06-03 | 9,118 | $7.33 | $67K |
| 2026-05-27 | 309 | $7.59 | $2K |
| 2026-05-19 | 679 | $7.59 | $5K |
| 2026-04-23 | 49 | $8.44 | $414 |
| 2026-04-22 | 1 | $8.50 | $9 |
| 2026-04-14 | 960 | $8.58 | $8K |
| 2026-04-13 | 3 | $8.32 | $25 |
| 2026-03-16 | 2,642 | $8.63 | $23K |
| 2026-02-23 | 699 | $8.55 | $6K |
| 2026-02-18 | 113 | $8.28 | $936 |
| 2026-02-13 | 285 | $8.22 | $2K |
| 2026-02-06 | 973 | $13.40 | $13K |
| 2026-02-03 | 1,091 | $15.15 | $17K |
| 2026-02-02 | 1,674 | $14.92 | $25K |
| 2026-01-29 | 70 | $15.14 | $1K |
| 2026-01-27 | 3 | $15.63 | $47 |
Insider trades
SEC Form 4, newest first. JSONInsiders at MCRB reported 4 open-market sells worth $2K in the last 90 days and no open-market buys. Latest filing: DesRosier Thomas (See Remarks) on 2026-08-17.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-08-17 | DesRosier Thomas | See Remarks | Sell | 82 | $4.55 | $373 | 8K |
| 2026-08-17 | Henn Matthew R | See Remarks | Sell | 81 | $4.55 | $369 | 8K |
| 2026-08-17 | Shaff Eric D. | Director | Sell | 263 | $4.55 | $1K | 12K |
| 2026-08-17 | Brady Kelly | See Remarks | Sell | 64 | $4.55 | $291 | 9K |
| 2026-08-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 245 | price not stated in the filing | not stated | 8K |
| 2026-08-15 | Henn Matthew R | See Remarks | Exercise or conversion | 238 | price not stated in the filing | not stated | 8K |
| 2026-08-15 | Shaff Eric D. | Director | Exercise or conversion | 722 | price not stated in the filing | not stated | 13K |
| 2026-08-15 | Brady Kelly | See Remarks | Exercise or conversion | 181 | price not stated in the filing | not stated | 9K |
| 2026-05-18 | Henn Matthew R | See Remarks | Sell | 77 | $7.53 | $580 | 8K |
| 2026-05-18 | DesRosier Thomas | See Remarks | Sell | 79 | $7.53 | $595 | 8K |
| 2026-05-18 | Brady Kelly | See Remarks | Sell | 59 | $7.53 | $444 | 9K |
| 2026-05-18 | Shaff Eric D. | Director | Sell | 259 | $7.53 | $2K | 12K |
| 2026-05-15 | Henn Matthew R | See Remarks | Exercise or conversion | 238 | price not stated in the filing | not stated | 8K |
| 2026-05-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 244 | price not stated in the filing | not stated | 8K |
| 2026-05-15 | Brady Kelly | See Remarks | Exercise or conversion | 180 | price not stated in the filing | not stated | 9K |
| 2026-05-15 | Shaff Eric D. | Director | Exercise or conversion | 722 | price not stated in the filing | not stated | 12K |
| 2026-02-15 | Henn Matthew R | See Remarks | Sell | 89 | $8.47 | $754 | 8K |
| 2026-02-15 | Henn Matthew R | See Remarks | Exercise or conversion | 239 | price not stated in the filing | not stated | 8K |
| 2026-02-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 244 | price not stated in the filing | not stated | 8K |
| 2026-02-15 | DesRosier Thomas | See Remarks | Sell | 78 | $8.47 | $661 | 8K |
| 2026-02-15 | Shaff Eric D. | Director | Sell | 259 | $8.47 | $2K | 12K |
| 2026-02-15 | Young Teresa L. | See Remarks | Sell | 75 | $8.47 | $635 | 9K |
| 2026-02-15 | Young Teresa L. | See Remarks | Exercise or conversion | 231 | price not stated in the filing | not stated | 9K |
| 2026-02-15 | Shaff Eric D. | Director | Exercise or conversion | 723 | price not stated in the filing | not stated | 12K |
| 2025-11-15 | Henn Matthew R | See Remarks | Exercise or conversion | 140 | price not stated in the filing | not stated | 9K |
| 2025-11-15 | Henn Matthew R | See Remarks | Exercise or conversion | 4K | price not stated in the filing | not stated | 9K |
| 2025-11-15 | Henn Matthew R | See Remarks | Exercise or conversion | 98 | price not stated in the filing | not stated | 9K |
| 2025-11-15 | Henn Matthew R | See Remarks | Sell | 1K | $17.30 | $22K | 8K |
| 2025-11-15 | Shaff Eric D. | Director | Exercise or conversion | 390 | price not stated in the filing | not stated | 11K |
| 2025-11-15 | Shaff Eric D. | Director | Exercise or conversion | 331 | price not stated in the filing | not stated | 11K |
| 2025-11-15 | Shaff Eric D. | Director | Sell | 217 | $17.30 | $4K | 11K |
| 2025-11-15 | Young Teresa L. | See Remarks | Exercise or conversion | 132 | price not stated in the filing | not stated | 9K |
| 2025-11-15 | Young Teresa L. | See Remarks | Exercise or conversion | 98 | price not stated in the filing | not stated | 9K |
| 2025-11-15 | Young Teresa L. | See Remarks | Exercise or conversion | 4K | price not stated in the filing | not stated | 9K |
| 2025-11-15 | Young Teresa L. | See Remarks | Sell | 1K | $17.30 | $18K | 8K |
| 2025-11-15 | DesRosier Thomas | See Remarks | Sell | 76 | $17.30 | $1K | 8K |
| 2025-11-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 112 | price not stated in the filing | not stated | 8K |
| 2025-11-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 132 | price not stated in the filing | not stated | 8K |
| 2025-08-18 | Young Teresa L. | See Remarks | Sell | 59 | $16.65 | $982 | 5K |
| 2025-08-18 | Henn Matthew R | See Remarks | Sell | 73 | $16.65 | $1K | 5K |
| 2025-08-18 | DesRosier Thomas | See Remarks | Sell | 76 | $16.65 | $1K | 7K |
| 2025-08-18 | Shaff Eric D. | Director | Sell | 217 | $16.65 | $4K | 11K |
| 2025-08-15 | Young Teresa L. | See Remarks | Exercise or conversion | 97 | price not stated in the filing | not stated | 5K |
| 2025-08-15 | Young Teresa L. | See Remarks | Exercise or conversion | 133 | price not stated in the filing | not stated | 5K |
| 2025-08-15 | Henn Matthew R | See Remarks | Exercise or conversion | 141 | price not stated in the filing | not stated | 5K |
| 2025-08-15 | Henn Matthew R | See Remarks | Exercise or conversion | 97 | price not stated in the filing | not stated | 5K |
| 2025-08-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 133 | price not stated in the filing | not stated | 7K |
| 2025-08-15 | DesRosier Thomas | See Remarks | Exercise or conversion | 111 | price not stated in the filing | not stated | 8K |
| 2025-08-15 | Shaff Eric D. | Director | Exercise or conversion | 391 | price not stated in the filing | not stated | 10K |
| 2025-08-15 | Shaff Eric D. | Director | Exercise or conversion | 333 | price not stated in the filing | not stated | 11K |
| 2025-05-16 | Henn Matthew R | See Remarks | Sell | 77 | $7.28 | $561 | 4K |
| 2025-05-16 | Shaff Eric D. | CEO and President | Sell | 220 | $7.28 | $2K | 10K |
| 2025-05-16 | Young Teresa L. | See Remarks | Sell | 63 | $7.28 | $459 | 5K |
| 2025-05-15 | Henn Matthew R | See Remarks | Exercise or conversion | 98 | price not stated in the filing | not stated | 4K |
| 2025-05-15 | Henn Matthew R | See Remarks | Exercise or conversion | 140 | price not stated in the filing | not stated | 4K |
| 2025-05-15 | DesRosier Thomas | Chief Legal Officer and EVP | Exercise or conversion | 111 | price not stated in the filing | not stated | 7K |
| 2025-05-15 | DesRosier Thomas | Chief Legal Officer and EVP | Exercise or conversion | 133 | price not stated in the filing | not stated | 7K |
| 2025-05-15 | DesRosier Thomas | Chief Legal Officer and EVP | Sell | 79 | $7.28 | $575 | 7K |
| 2025-05-15 | Shaff Eric D. | CEO and President | Exercise or conversion | 331 | price not stated in the filing | not stated | 10K |
| 2025-05-15 | Shaff Eric D. | CEO and President | Exercise or conversion | 390 | price not stated in the filing | not stated | 10K |
| 2025-05-15 | Young Teresa L. | See Remarks | Exercise or conversion | 98 | price not stated in the filing | not stated | 5K |
| 2025-05-15 | Young Teresa L. | See Remarks | Exercise or conversion | 133 | price not stated in the filing | not stated | 5K |
| 2025-02-18 | von Moltke Lisa | See Remarks | Sell | 4K | $0.81 | $4K | 40K |
| 2025-02-18 | DesRosier Thomas | Chief Legal Officer and EVP | Sell | 4K | $0.81 | $3K | 142K |
| 2025-02-18 | Shaff Eric D. | CEO and President | Sell | 13K | $0.81 | $10K | 192K |
| 2025-02-18 | Henn Matthew R. | See Remarks | Sell | 4K | $0.81 | $3K | 84K |
| 2025-02-18 | Young Teresa L. | See Remarks | Sell | 3K | $0.81 | $3K | 98K |
| 2025-02-15 | von Moltke Lisa | See Remarks | Exercise or conversion | 3K | price not stated in the filing | not stated | 35K |
| 2025-02-15 | von Moltke Lisa | See Remarks | Exercise or conversion | 9K | price not stated in the filing | not stated | 44K |
| 2025-02-15 | DesRosier Thomas | Chief Legal Officer and EVP | Exercise or conversion | 3K | price not stated in the filing | not stated | 138K |
| 2025-02-15 | DesRosier Thomas | Chief Legal Officer and EVP | Exercise or conversion | 9K | price not stated in the filing | not stated | 147K |
| 2025-02-15 | Shaff Eric D. | CEO and President | Exercise or conversion | 27K | price not stated in the filing | not stated | 205K |
| 2025-02-15 | Shaff Eric D. | CEO and President | Exercise or conversion | 8K | price not stated in the filing | not stated | 178K |
| 2025-02-15 | Henn Matthew R. | See Remarks | Exercise or conversion | 3K | price not stated in the filing | not stated | 81K |
| 2025-02-15 | Henn Matthew R. | See Remarks | Exercise or conversion | 8K | price not stated in the filing | not stated | 88K |
| 2025-02-15 | Young Teresa L. | See Remarks | Exercise or conversion | 8K | price not stated in the filing | not stated | 101K |
| 2025-02-15 | Young Teresa L. | See Remarks | Exercise or conversion | 3K | price not stated in the filing | not stated | 93K |
| 2024-11-18 | Shaff Eric D. | CEO and President | Sell | 3K | $0.54 | $1K | 170K |
| 2024-11-18 | Henn Matthew R. | See Remarks | Sell | 927 | $0.54 | $501 | 78K |
| 2024-11-18 | Young Teresa L. | See Remarks | Sell | 735 | $0.54 | $397 | 90K |
| 2024-11-18 | von Moltke Lisa | See Remarks | Sell | 977 | $0.54 | $528 | 32K |
| 2024-11-18 | DesRosier Thomas | Chief Legal Officer and EVP | Sell | 878 | $0.54 | $474 | 135K |
| 2024-11-15 | Shaff Eric D. | CEO and President | Exercise or conversion | 8K | price not stated in the filing | not stated | 173K |
| 2024-11-15 | Henn Matthew R. | See Remarks | Exercise or conversion | 3K | price not stated in the filing | not stated | 79K |
| 2024-11-15 | Young Teresa L. | See Remarks | Exercise or conversion | 3K | price not stated in the filing | not stated | 91K |
| 2024-11-15 | von Moltke Lisa | See Remarks | Exercise or conversion | 3K | price not stated in the filing | not stated | 33K |
| 2024-11-15 | DesRosier Thomas | Chief Legal Officer and EVP | Exercise or conversion | 3K | price not stated in the filing | not stated | 136K |
| 2024-10-28 | Young Teresa L. | See Remarks | Sell | 3K | $0.69 | $2K | 88K |
| 2024-10-28 | Shaff Eric D. | CEO and President | Sell | 9K | $0.69 | $6K | 165K |
| 2024-10-28 | DesRosier Thomas | Chief Legal Officer and EVP | Sell | 4K | $0.69 | $3K | 133K |
| 2024-10-28 | Henn Matthew R. | See Remarks | Sell | 4K | $0.69 | $3K | 76K |
| 2024-10-28 | von Moltke Lisa | See Remarks | Sell | 4K | $0.69 | $3K | 30K |
| 2024-10-27 | Young Teresa L. | See Remarks | Exercise or conversion | 11K | $0.00 | $0 | 91K |
| 2024-10-27 | Shaff Eric D. | CEO and President | Exercise or conversion | 28K | $0.00 | $0 | 174K |
| 2024-10-27 | DesRosier Thomas | Chief Legal Officer and EVP | Exercise or conversion | 14K | $0.00 | $0 | 138K |
| 2024-10-27 | Henn Matthew R. | See Remarks | Exercise or conversion | 13K | $0.00 | $0 | 80K |
| 2024-10-27 | von Moltke Lisa | See Remarks | Exercise or conversion | 14K | $0.00 | $0 | 35K |
| 2024-08-16 | Ege David S. | See Remarks | Sell | 1K | $0.84 | $948 | 78K |
| 2024-08-16 | Young Teresa L. | See Remarks | Sell | 728 | $0.84 | $612 | 80K |
| 2024-08-16 | Shaff Eric D. | CEO and President | Sell | 3K | $0.84 | $2K | 146K |
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.
Planned sales (Form 144)
Newest first. JSON2 Form 144 notices on file for MCRB worth $79K at the prices reported; 0 in the last 90 days worth $0. Latest: TERESA L YOUNG filed on 2026-05-19 to sell 167 shares ($1K) from 2026-05-19.
| Filed | Seller | Shares | Market value | Of outstanding | Sale from | Broker |
|---|---|---|---|---|---|---|
| 2026-05-19 | TERESA L YOUNGOfficer | 167 | $1K | 0.002% | 2026-05-19 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-03-17 | TERESA L YOUNGOfficer | 9K | $78K | 0.089% | 2026-03-17 | Morgan Stanley Smith Barney LLC Executive Financial Services |
13F holders
Tracked managers holding MCRB at their latest 13F. JSON1 of the 30 tracked managers held MCRB at their latest 13F, $83K in total at quarter-end prices. Citadel Advisors is the largest at $83K (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 1 added shares and 0 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Citadel Advisors | 2026-06-30 | 11K | $83K | 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
Seres Therapeutics 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 Seres Therapeutics (MCRB), SEC CIK 1609809, 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 2026-10-02.JSON and CSV
- Planned sales
- SEC EDGAR Form 144Source: SEC.New notices appear shortly after the SEC posts them; a notice is filed on or before the sale. Latest 2026-05-19.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 2026-05-05.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 2026-08-17.JSON and CSV
- Company record
- EDGAR filing index for CIK 1609809Ticker, 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 MCRB is sold short?
312,339 shares were held short at the 2026-10-15 settlement, 3.5 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 MCRB's daily short volume?
On 2026-11-02, 13,873 of the 21,728 MCRB shares reported to FINRA were sold short, 63.8% of the day's reported volume. Short volume is a flow for one day, not a position.
Does MCRB have fails to deliver?
The SEC's latest file shows 10,817 MCRB shares failed to deliver at settlement 2026-10-02. Fails are reported per settlement date and published twice a month with a lag.
Are MCRB insiders buying or selling?
Insiders at MCRB reported 4 open-market sells worth $2K in the last 90 days and no open-market buys. Latest filing: DesRosier Thomas (See Remarks) on 2026-08-17.
Have MCRB insiders filed to sell?
2 Form 144 notices on file for MCRB worth $79K at the prices reported; 0 in the last 90 days worth $0. Latest: TERESA L YOUNG filed on 2026-05-19 to sell 167 shares ($1K) from 2026-05-19.
Which tracked 13F managers own MCRB?
1 of the 30 tracked 13F managers held MCRB shares at their latest filing, $83K in all. The largest: Ken Griffin's Citadel Advisors (11K shares, $83K).
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.