Seaport Therapeutics (SPTX)
Seaport Therapeutics on one page: short interest, daily short volume, fails to deliver, large holders, 13F holders, earnings dates and insider trades. Listed on Nasdaq.
3.7M
Short interest
settlement 2026-10-15
17.9
Days to cover
+9.0 days vs prior
95.3%
Short share of volume
2026-11-03
4,320
Fails to deliver
settlement 2026-10-14
Mon 7 Jun
Next earnings
estimated date
$0
Insider flow, 90 days
0 buys, 0 sells
As of 2026-11-03.
Short interest
FINRA, twice a month. The newest 11 settlements in the table. JSONAs of 15 October 2026, short interest in SPTX is 3,718,915 shares, up 570,034 shares over the last month. Over the last 11 readings it ranged from 1,459,469 shares (15 May 2026) to 3,718,915 shares (15 October 2026). The latest reading sits at the top of that range. At the reported average volume of 208K shares a day that is 17.9 days to cover.
| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 3,718,915 | +1.9% | 208,075 | 17.87 |
| 2026-09-30 | 3,649,879 | +15.9% | 408,953 | 8.92 |
| 2026-09-15 | 3,148,881 | -0.1% | 152,218 | 20.69 |
| 2026-08-31 | 3,152,409 | +4.6% | 121,336 | 25.98 |
| 2026-08-14 | 3,012,877 | +9.2% | 119,904 | 25.13 |
| 2026-07-31 | 2,758,029 | +39.3% | 89,684 | 30.75 |
| 2026-07-15 | 1,980,276 | -28.8% | 161,227 | 12.28 |
| 2026-06-30 | 2,779,385 | +43.4% | 362,395 | 7.67 |
| 2026-06-15 | 1,938,933 | +10.7% | 119,439 | 16.23 |
| 2026-05-29 | 1,752,377 | +20.1% | 217,003 | 8.08 |
| 2026-05-15 | 1,459,469 | +100.0% | 850,464 | 1.72 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 3 November 2026, the short share of SPTX volume is 95.3%, up 4.3 points over the last five sessions. Over the last 30 readings it ranged from 29.6% (2 November 2026) to 95.3% (3 November 2026). The latest reading sits at the top of that range. The latest reading is 19.0 points above the 30-session average of 76.3%, on 175K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-03 | 167K | 175K | 95.3% | 0 |
| 2026-11-02 | 104K | 351K | 29.6% | 0 |
| 2026-10-30 | 193K | 205K | 94.2% | 0 |
| 2026-10-29 | 120K | 129K | 92.3% | 0 |
| 2026-10-28 | 93K | 120K | 77.0% | 18,522 |
| 2026-10-27 | 64K | 70K | 91.0% | 0 |
| 2026-10-26 | 44K | 52K | 84.7% | 0 |
| 2026-10-23 | 40K | 45K | 87.8% | 0 |
| 2026-10-22 | 35K | 44K | 79.5% | 0 |
| 2026-10-21 | 36K | 42K | 84.2% | 0 |
| 2026-10-20 | 26K | 50K | 52.2% | 0 |
| 2026-10-19 | 27K | 54K | 49.6% | 0 |
| 2026-10-16 | 25K | 41K | 60.4% | 0 |
| 2026-10-15 | 33K | 62K | 53.2% | 0 |
| 2026-10-14 | 28K | 55K | 51.0% | 0 |
| 2026-10-13 | 45K | 68K | 67.0% | 0 |
| 2026-10-12 | 30K | 39K | 76.2% | 0 |
| 2026-10-09 | 43K | 71K | 60.8% | 0 |
| 2026-10-08 | 44K | 59K | 75.4% | 0 |
| 2026-10-07 | 67K | 75K | 89.4% | 0 |
| 2026-10-06 | 70K | 79K | 88.6% | 0 |
| 2026-10-05 | 53K | 59K | 88.9% | 0 |
| 2026-10-02 | 67K | 74K | 90.8% | 0 |
| 2026-10-01 | 50K | 58K | 85.2% | 0 |
| 2026-09-30 | 52K | 63K | 82.7% | 0 |
| 2026-09-29 | 66K | 115K | 57.4% | 320 |
| 2026-09-28 | 73K | 101K | 71.9% | 2,476 |
| 2026-09-25 | 47K | 53K | 88.9% | 0 |
| 2026-09-24 | 47K | 50K | 93.7% | 0 |
| 2026-09-23 | 60K | 67K | 89.8% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 14 October 2026, the fails-to-deliver balance in SPTX is 4,320 shares, down 11,929 shares over the last settlement date. Over the last 30 readings it ranged from 3 shares (30 September 2026) to 58,886 shares (21 September 2026). The latest reading sits at the bottom of that range.
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-14 | 4,320 | $16.08 | $69K |
| 2026-10-08 | 16,249 | $17.93 | $291K |
| 2026-10-07 | 42 | $17.37 | $730 |
| 2026-10-06 | 151 | $18.50 | $3K |
| 2026-10-02 | 3,859 | $18.95 | $73K |
| 2026-10-01 | 3,164 | $20.17 | $64K |
| 2026-09-30 | 3 | $18.69 | $56 |
| 2026-09-29 | 4,310 | $19.64 | $85K |
| 2026-09-25 | 82 | $21.12 | $2K |
| 2026-09-24 | 12,260 | $21.29 | $261K |
| 2026-09-23 | 2,305 | $22.39 | $52K |
| 2026-09-22 | 2,426 | $21.12 | $51K |
| 2026-09-21 | 58,886 | $21.39 | $1.3M |
| 2026-09-18 | 1,986 | $21.82 | $43K |
| 2026-09-17 | 2,049 | $22.14 | $45K |
| 2026-09-16 | 4,041 | $22.96 | $93K |
| 2026-09-15 | 276 | $24.70 | $7K |
| 2026-09-11 | 2,429 | $23.28 | $57K |
| 2026-09-08 | 443 | $24.86 | $11K |
| 2026-09-03 | 791 | $24.91 | $20K |
| 2026-09-01 | 236 | $23.68 | $6K |
| 2026-08-28 | 600 | $26.25 | $16K |
| 2026-08-26 | 827 | $24.83 | $21K |
| 2026-08-18 | 2,923 | $24.40 | $71K |
| 2026-08-17 | 30,355 | $24.22 | $735K |
| 2026-08-13 | 1,257 | $23.80 | $30K |
| 2026-08-12 | 249 | $23.36 | $6K |
| 2026-08-11 | 4,553 | $23.02 | $105K |
| 2026-08-10 | 15 | $23.62 | $354 |
| 2026-08-07 | 8,233 | $23.09 | $190K |
Insider trades
SEC Form 4, newest first. JSONNo open-market insider trades were reported for SPTX in the last 90 days. The most recent filings are listed below. Latest filing: HOMBACH ROBERT J. (Director) on 2026-06-22.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-06-22 | HOMBACH ROBERT J. | Director | Buy | 13K | $18.14 | $236K | 13K |
| 2026-05-04 | Loebel Antony | Chief Medical Officer | Conversion | 20K | price not stated in the filing | not stated | 20K |
| 2026-05-04 | ARCH Venture Partners XII, L.P. | TenPercentOwner | Conversion | 2.5M | price not stated in the filing | not stated | 2.5M |
| 2026-05-04 | ARCH Venture Partners XII, L.P. | TenPercentOwner | Conversion | 2.7M | price not stated in the filing | not stated | 5.2M |
| 2026-05-04 | ARCH Venture Partners XII, L.P. | TenPercentOwner | Buy | 1.1M | $18.00 | $19.8M | 6.3M |
| 2026-05-04 | PAUL STEVEN M | Director | Conversion | 67K | price not stated in the filing | not stated | 863K |
| 2026-05-04 | Torres Denice | Director | Conversion | 13K | price not stated in the filing | not stated | 13K |
| 2026-05-04 | Chen Michael Cunyuan | Chief Scientific Officer | Conversion | 3K | price not stated in the filing | not stated | 3K |
| 2026-05-04 | Gladstein Lana | General Counsel | Conversion | 34K | price not stated in the filing | not stated | 34K |
| 2026-05-04 | White Lauren | Chief Financial Officer | Conversion | 7K | price not stated in the filing | not stated | 7K |
| 2026-05-04 | HEALY JAMES | Director | Conversion | 1.9M | price not stated in the filing | not stated | 1.9M |
| 2026-05-04 | HEALY JAMES | Director | Conversion | 804K | price not stated in the filing | not stated | 2.7M |
| 2026-05-04 | PureTech Health plc | TenPercentOwner | Conversion | 12.7M | price not stated in the filing | not stated | 13.0M |
| 2026-05-04 | PureTech Health plc | TenPercentOwner | Conversion | 965K | price not stated in the filing | not stated | 16.7M |
| 2026-05-04 | PureTech Health plc | TenPercentOwner | Conversion | 2.7M | price not stated in the filing | not stated | 15.7M |
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. JSON28 holders report 5% or more of SPTX in their latest filing, 21 on Schedule 13D (active intent). The largest reported stake is PureTech Health plc at 31.2% of the class (16,685,013 shares), filed 2026-08-14 for an event on 2026-06-30.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-08-14 | 13G | PureTech Health plccorporation | 16.7M | 31.2% | 2026-06-30 |
| 2026-08-14 | 13G | PureTech LYT, Inc.corporation | 16.7M | 31.2% | 2026-06-30 |
| 2026-08-14 | 13G | PureTech Health LLCother entity | 16.7M | 31.2% | 2026-06-30 |
| 2026-08-05 | 13G | Zohar Daphneindividual | 5.2M | 9.1% | 2026-06-30 |
| 2026-08-05 | 13G | PAUL STEVEN Mindividual | 3.5M | 6.3% | 2026-06-30 |
| 2026-05-11 | 13G | THE GOLDMAN SACHS GROUP, INC.parent holding company, corporation | 2.8M | 5.5% | 2026-05-06 |
| 2026-05-11 | 13G | GOLDMAN SACHS & CO. LLCbroker-dealer, other entity, investment adviser | 2.8M | 5.5% | 2026-05-06 |
| 2026-05-11 | 13D | General Atlantic Partners (Lux) SCSppartnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic GenPar, L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | GAP Coinvestments III, LLCother entity | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | GAP Coinvestments IV, LLCother entity | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | GAP Coinvestments V, LLCother entity | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic GenPar (Lux) SCSppartnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic (Lux) S.a r.l.parent holding company | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic GenPar (Bermuda), L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | GAP (Bermuda) L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | GAP Coinvestments CDA, L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic, L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic (SPV) GP, LLCother entity | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic Partners 100, L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-11 | 13D | General Atlantic (SP), L.P.partnership | 6.1M | 11.5% | 2026-05-04 |
| 2026-05-06 | 13D | ARCH Venture Fund XII, L.P.partnership | 6.3M | 11.9% | 2026-05-04 |
| 2026-05-06 | 13D | ARCH Venture Partners XII, L.P.partnership | 6.3M | 11.9% | 2026-05-04 |
| 2026-05-06 | 13D | ARCH Venture Partners XII, LLCother entity | 6.3M | 11.9% | 2026-05-04 |
| 2026-05-06 | 13D | Robert Nelsenindividual | 6.3M | 11.9% | 2026-05-04 |
| 2026-05-06 | 13D | Keith Crandellindividual | 6.3M | 11.9% | 2026-05-04 |
| 2026-05-06 | 13D | Kristina Burowindividual | 6.3M | 11.9% | 2026-05-04 |
| 2026-05-06 | 13D | Steven Gillisindividual | 6.3M | 11.9% | 2026-05-04 |
13F holders
Tracked managers holding SPTX at their latest 13F. JSON2 of the 30 tracked managers held SPTX at their latest 13F, $5.1M in total at quarter-end prices. Citadel Advisors is the largest at $4.2M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 2 added shares and 0 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Citadel Advisors | 2026-06-30 | 191K | $4.2M | 0.00% | new |
| Millennium Management | 2026-06-30 | 45K | $985K | 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
Seaport 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 Seaport Therapeutics (SPTX), SEC CIK 2042347, 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 2026-11-03.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 2026-08-14.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 2026-11-02.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 2026-06-22.JSON and CSV
- Company record
- EDGAR filing index for CIK 2042347Ticker, 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 SPTX is sold short?
What is SPTX's daily short volume?
Does SPTX have fails to deliver?
Are SPTX insiders buying or selling?
Who owns 5% or more of SPTX?
Which tracked 13F managers own SPTX?
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.