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HowShorted

How shorted is Aspen Aerogels, Inc.? ASPN

#564most shorted US stockof 3,805 ranked stocks, more shorted than 85%

10.92%
of shares outstanding reported short · settlement date 15 Sep 2026
vs previous report
+0.79
5 reports (~10 weeks)
+2.35
days to cover
13.93
Aggregate net short position time series for Aspen Aerogels, Inc.

Markers along the chart's base: ▲ results announced (an 8-K reporting results was filed) ▲ quarterly or annual report filed. Dates are SEC filing dates; hover a point to see events since the previous settlement.

Days to cover

FINRA's own figure: reported shares short divided by the stock's average daily trading volume, published alongside each settlement. It expresses the short position in days of typical trading rather than as a percentage of the company; the two can move differently.

Aggregate net short position time series for Aspen Aerogels, Inc. days to cover

Short interest around results

For each results announcement (an 8-K reporting results, by its SEC filing date), the FINRA settlement before it and the first one after. Settlements fall twice a month, so the two figures can sit up to a month apart and much else changes in between: this shows what was reported, not why.

Reported short interest before and after each results announcement
Results filedSettlement beforeSettlement afterChange
6 Aug 202610.68% 31 Jul 20269.74% 14 Aug 2026−0.94
7 May 20269.66% 30 Apr 20269.34% 15 May 2026−0.32
25 Feb 20268.99% 13 Feb 20269.01% 27 Feb 2026+0.02
6 Nov 202510.37% 31 Oct 202511.70% 14 Nov 2025+1.33
7 Aug 202510.37% 31 Jul 202511.17% 15 Aug 2025+0.80
8 May 202510.22% 30 Apr 20258.53% 15 May 2025−1.69
12 Feb 202513.18% 31 Jan 202513.98% 14 Feb 2025+0.80
6 Nov 202411.04% 31 Oct 202411.29% 15 Nov 2024+0.25

Fails to deliver

The SEC's fails-to-deliver figure for ASPN: the aggregate net balance of shares that failed to be delivered at each settlement date, published by the SEC twice a month and shown here verbatim for the trailing window. A balance is not a daily flow, and a fail has many ordinary causes; the SEC says it cannot guarantee the accuracy of the data. See what fails to deliver are and the largest balances today.

Latest balance
962
14 Sep 2026
Highest in window
59,814
12 Feb 2026
Days with a balance
48
Window
16 Sep 2025 to 14 Sep 2026
Aggregate net short position time series for Aspen Aerogels, Inc. fails to deliver

Source: U.S. Securities and Exchange Commission, fails-to-deliver data (public domain). Only settlement days with a positive balance appear; the largest balance in the window was 60K shares.

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Sector: Consumer retail

History

Full reported short interest history
Settlement dateShort %Change
15 Sep 202610.92%+0.79
31 Aug 202610.13%+0.39
14 Aug 20269.74%−0.94
31 Jul 202610.68%+0.75
15 Jul 20269.93%+1.36
30 Jun 20268.57%−0.02
15 Jun 20268.59%+0.03
29 May 20268.56%−0.78
15 May 20269.34%−0.32
30 Apr 20269.66%+1.19
15 Apr 20268.47%+0.95
31 Mar 20267.52%−1.00
13 Mar 20268.52%−0.49
27 Feb 20269.01%+0.02
13 Feb 20268.99%−0.20
30 Jan 20269.19%−1.37
15 Jan 202610.56%−0.51
31 Dec 202511.07%+0.93
15 Dec 202510.14%−0.22
28 Nov 202510.36%−1.34
14 Nov 202511.70%+1.33
31 Oct 202510.37%−0.05
15 Oct 202510.42%−2.07
30 Sep 202512.49%+1.41
15 Sep 202511.08%−0.21
29 Aug 202511.29%+0.12
15 Aug 202511.17%+0.80
31 Jul 202510.37%+0.26
15 Jul 202510.11%−0.79
30 Jun 202510.90%−0.08
13 Jun 202510.98%−0.39
30 May 202511.37%+2.84
15 May 20258.53%−1.69
30 Apr 202510.22%−0.91
15 Apr 202511.13%−0.08
31 Mar 202511.21%+0.33
14 Mar 202510.88%−0.96
28 Feb 202511.84%−2.14
14 Feb 202513.98%+0.80
31 Jan 202513.18%+0.36
15 Jan 202512.82%+0.85
31 Dec 202411.97%+1.03
13 Dec 202410.94%−0.17
29 Nov 202411.11%−0.18
15 Nov 202411.29%+0.25
31 Oct 202411.04%−0.01
15 Oct 202411.05%+2.64
30 Sep 20248.41%+0.64
13 Sep 20247.77%+0.61
30 Aug 20247.16%+1.25
15 Aug 20245.91%+0.08
31 Jul 20245.83%−0.21
15 Jul 20246.04%+0.42
28 Jun 20245.62%+0.64
14 Jun 20244.98%+0.15
31 May 20244.83%−1.04
15 May 20245.87%−0.58
30 Apr 20246.45%+0.17
15 Apr 20246.28%+0.29
28 Mar 20245.99%−0.25
15 Mar 20246.24%−0.26
29 Feb 20246.50%−0.12
15 Feb 20246.62%+0.15
31 Jan 20246.47%−0.17
12 Jan 20246.64%−0.86
29 Dec 20237.50%+0.04
15 Dec 20237.46%−0.78
30 Nov 20238.24%−0.09
15 Nov 20238.33%−0.96
31 Oct 20239.29%+1.09
13 Oct 20238.20%−0.14
29 Sep 20238.34%+0.57
15 Sep 20237.77%−0.17
31 Aug 20237.94%+0.62
15 Aug 20237.32%+0.50
31 Jul 20236.82%−1.01
14 Jul 20237.83%+0.29
30 Jun 20237.54%−0.02
15 Jun 20237.56%+0.78
31 May 20236.78%+0.62
15 May 20236.16%+0.30
28 Apr 20235.86%+0.65
14 Apr 20235.21%+0.31
31 Mar 20234.90%+0.55
15 Mar 20234.35%−3.01
28 Feb 20237.36%+0.25
15 Feb 20237.11%+0.48
31 Jan 20236.63%−0.06
13 Jan 20236.69%−1.29
30 Dec 20227.98%+0.67
15 Dec 20227.31%−0.25
30 Nov 20227.56%+0.51
15 Nov 20227.05%+0.89
31 Oct 20226.16%−0.21
14 Oct 20226.37%−0.13
30 Sep 20226.50%−0.27
15 Sep 20226.77%−0.27
31 Aug 20227.04%+0.13
15 Aug 20226.91%−1.33
29 Jul 20228.24%+0.34
15 Jul 20227.90%+1.92
30 Jun 20225.98%−0.50
15 Jun 20226.48%+0.89
31 May 20225.59%+0.45
13 May 20225.14%+0.36
29 Apr 20224.78%+0.02
14 Apr 20224.76%+0.04
31 Mar 20224.72%+0.68
15 Mar 20224.04%−0.08
28 Feb 20224.12%−1.05
15 Feb 20225.17%+1.59
31 Jan 20223.58%+1.10
14 Jan 20222.48%+0.41
31 Dec 20212.07%+0.67
15 Dec 20211.40%+0.15
30 Nov 20211.25%−0.21
15 Nov 20211.46%−0.12
29 Oct 20211.58%+0.09
15 Oct 20211.49%−0.01
30 Sep 20211.50%−0.14
15 Sep 20211.64%+0.09
31 Aug 20211.55%−0.63
13 Aug 20212.18%−0.52
30 Jul 20212.70%+0.18
15 Jul 20212.52%−0.90
30 Jun 20213.42%−0.22
15 Jun 20213.64%+0.05
28 May 20213.59%+0.21
14 May 20213.38%+0.25
30 Apr 20213.13%+0.62
15 Apr 20212.51%+0.21
31 Mar 20212.30%+0.21
15 Mar 20212.09%+0.01
26 Feb 20212.08%+0.21
12 Feb 20211.87%+0.09
29 Jan 20211.78%−0.23
15 Jan 20212.01%+0.15
31 Dec 20201.86%+0.68
15 Dec 20201.18%+0.18
30 Nov 20201.00%+0.08
13 Nov 20200.92%−0.44
30 Oct 20201.36%−0.39
15 Oct 20201.75%−0.15
30 Sep 20201.90%+0.40
15 Sep 20201.50%−0.12
31 Aug 20201.62%−0.03
14 Aug 20201.65%+1.43
15 Jun 20200.22%0.00
29 May 20200.22%−0.02
15 May 20200.24%−0.05
30 Apr 20200.29%−0.08
15 Apr 20200.37%−0.06
31 Mar 20200.43%−0.14
13 Mar 20200.57%−0.06
28 Feb 20200.63%+0.16
14 Feb 20200.47%+0.16
31 Jan 20200.31%+0.05
15 Jan 20200.26%+0.07
31 Dec 20190.19%−0.11
13 Dec 20190.30%+0.02
29 Nov 20190.28%−0.04
15 Nov 20190.32%−0.04
31 Oct 20190.36%−0.01
15 Oct 20190.37%+0.07
30 Sep 20190.30%+0.04
13 Sep 20190.26%−0.01
30 Aug 20190.27%−0.03
15 Aug 20190.30%−0.04
31 Jul 20190.34%−0.30
15 Jul 20190.64%+0.26
28 Jun 20190.38%+0.21
14 Jun 20190.17%+0.02
31 May 20190.15%−0.10
15 May 20190.25%+0.14
30 Apr 20190.11%−0.01
15 Apr 20190.12%+0.07
29 Mar 20190.05%−0.04
15 Mar 20190.09%+0.06
28 Feb 20190.03%−0.04
31 Jan 20190.07%+0.01
15 Jan 20190.06%−0.04
30 Nov 20180.10%−0.01
15 Nov 20180.11%−0.14
31 Oct 20180.25%+0.14
15 Oct 20180.11%−0.07
28 Sep 20180.18%+0.03
14 Sep 20180.15%0.00
31 Aug 20180.15%+0.01
15 Aug 20180.14%0.00
31 Jul 20180.14%−0.01
13 Jul 20180.15%−0.03
29 Jun 20180.18%−0.02
15 Jun 20180.20%−0.09
31 May 20180.29%−0.07
15 May 20180.36%−0.01
30 Apr 20180.37%−0.02
13 Apr 20180.39%+0.01
29 Mar 20180.38%+0.03
15 Mar 20180.35%+0.08
28 Feb 20180.27%+0.08
15 Feb 20180.19%+0.05
31 Jan 20180.14%+0.04
12 Jan 20180.10%−0.06
29 Dec 20170.16%–

Newest first. Scroll inside the table for earlier dates, back to 29 Dec 2017.

Frequently asked questions

How shorted is Aspen Aerogels, Inc. right now?
10.92% of Aspen Aerogels, Inc.'s (ASPN) shares outstanding were reported short for settlement date 15 Sep 2026, per FINRA's consolidated short interest report. That makes it the 564th most shorted US stock, out of 3,805 we rank.
What does this number include?
FINRA member firms must report their short positions in all US equities twice a month; FINRA consolidates them per security. We divide that official share count by the company's shares outstanding from its SEC filings. This is the regulatory figure, not a daily estimate.
Why does it only update twice a month?
US short interest is reported for settlement on the 15th and the last business day of each month, and FINRA publishes the consolidated figures about nine business days later. That cadence is set by regulation; no daily official figure exists.
Is this ASPN's short float?
No. This is short interest as a percentage of shares outstanding, the count in the company's SEC filings. "Short float" divides the same FINRA short count by the public float, which excludes closely held shares, so it comes out higher for the same company. We publish no float estimates: the float is not a regulatory figure.
What is ASPN's days to cover?
13.93 days for settlement date 15 Sep 2026: FINRA's own short interest ratio, the reported shares short divided by average daily trading volume. It is published in the same FINRA file and shown verbatim; we hold no volume data ourselves.
Which funds are short?
US public short interest is aggregate-only: individual short sellers are not named. Only some EU markets publish named positions.