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HowShorted

How shorted is Quantum-Si Incorporated Class? QSI

#1,393most shorted US stockof 3,805 ranked stocks, more shorted than 63%

5.96%
of shares outstanding reported short · settlement date 15 Sep 2026
vs previous report
−0.64
5 reports (~10 weeks)
−2.03
days to cover
10.32
Aggregate net short position time series for Quantum-Si Incorporated Class

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 Quantum-Si Incorporated Class 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
13 Aug 20267.08% 31 Jul 20266.52% 14 Aug 2026−0.56
7 May 202610.61% 30 Apr 202610.68% 15 May 2026+0.07
3 Mar 20269.77% 27 Feb 20269.94% 13 Mar 2026+0.17
5 Nov 20257.87% 31 Oct 20257.33% 14 Nov 2025−0.54
5 Aug 202510.77% 31 Jul 202511.58% 15 Aug 2025+0.81
15 May 202512.49% 30 Apr 202513.16% 30 May 2025+0.67
3 Mar 20259.65% 28 Feb 20259.09% 14 Mar 2025−0.56
12 Nov 20244.15% 31 Oct 20243.60% 15 Nov 2024−0.55

Fails to deliver

The SEC's fails-to-deliver figure for QSI: 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.

Last balance on file
4,999
8 Sep 2026
Highest in window
1,027,267
29 Jun 2026
Days with a balance
138
Window
16 Sep 2025 to 14 Sep 2026
Aggregate net short position time series for Quantum-Si Incorporated Class 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 1.0M shares.

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Sector: Technology

History

Full reported short interest history
Settlement dateShort %Change
15 Sep 20265.96%−0.64
31 Aug 20266.60%+0.08
14 Aug 20266.52%−0.56
31 Jul 20267.08%+0.59
15 Jul 20266.49%−1.50
30 Jun 20267.99%−2.35
15 Jun 202610.34%−0.13
29 May 202610.47%−0.21
15 May 202610.68%+0.07
30 Apr 202610.61%+0.01
15 Apr 202610.60%+0.37
31 Mar 202610.23%+0.29
13 Mar 20269.94%+0.17
27 Feb 20269.77%−0.13
13 Feb 20269.90%+1.15
30 Jan 20268.75%−0.22
15 Jan 20268.97%+0.03
31 Dec 20258.94%−0.03
15 Dec 20258.97%+0.23
28 Nov 20258.74%+1.41
14 Nov 20257.33%−0.54
31 Oct 20257.87%−1.98
15 Oct 20259.85%−0.98
30 Sep 202510.83%−0.03
15 Sep 202510.86%−0.22
29 Aug 202511.08%−0.50
15 Aug 202511.58%+0.81
31 Jul 202510.77%−2.01
15 Jul 202512.78%−0.30
30 Jun 202513.08%+0.09
13 Jun 202512.99%−0.17
30 May 202513.16%+0.36
15 May 202512.80%+0.31
30 Apr 202512.49%−0.03
15 Apr 202512.52%+1.29
31 Mar 202511.23%+2.14
14 Mar 20259.09%−0.56
28 Feb 20259.65%−3.52
14 Feb 202513.17%+0.05
31 Jan 202513.12%+0.10
15 Jan 202513.02%−3.55
31 Dec 202416.57%+8.67
13 Dec 20247.90%+1.53
29 Nov 20246.37%+2.77
15 Nov 20243.60%−0.55
31 Oct 20244.15%0.00
15 Oct 20244.15%−0.13
30 Sep 20244.28%+0.17
13 Sep 20244.11%−0.10
30 Aug 20244.21%+0.10
15 Aug 20244.11%−0.30
31 Jul 20244.41%−0.10
15 Jul 20244.51%−0.36
28 Jun 20244.87%−0.34
14 Jun 20245.21%−0.01
31 May 20245.22%+0.27
15 May 20244.95%−0.48
30 Apr 20245.43%+0.21
15 Apr 20245.22%−0.10
28 Mar 20245.32%+0.13
15 Mar 20245.19%−0.33
29 Feb 20245.52%−0.30
15 Feb 20245.82%+0.31
31 Jan 20245.51%−1.23
12 Jan 20246.74%+0.45
29 Dec 20236.29%+0.59
15 Dec 20235.70%−1.29
30 Nov 20236.99%+0.51
15 Nov 20236.48%+0.14
31 Oct 20236.34%−0.35
13 Oct 20236.69%−0.11
29 Sep 20236.80%−0.44
15 Sep 20237.24%+1.35
31 Aug 20235.89%−0.06
15 Aug 20235.95%+2.07
31 Jul 20233.88%+1.00
14 Jul 20232.88%+0.33
30 Jun 20232.55%+0.26
15 Jun 20232.29%−0.03
31 May 20232.32%−0.05
15 May 20232.37%−0.05
28 Apr 20232.42%+0.03
14 Apr 20232.39%−0.09
31 Mar 20232.48%+0.11
15 Mar 20232.37%+0.13
28 Feb 20232.24%+0.19
15 Feb 20232.05%−0.15
31 Jan 20232.20%−0.30
13 Jan 20232.50%−0.15
30 Dec 20222.65%+0.06
15 Dec 20222.59%−0.45
30 Nov 20223.04%−0.02
15 Nov 20223.06%+0.17
31 Oct 20222.89%−0.12
14 Oct 20223.01%+0.03
30 Sep 20222.98%−0.14
15 Sep 20223.12%−0.02
31 Aug 20223.14%−0.18
15 Aug 20223.32%+0.03
29 Jul 20223.29%−0.66
15 Jul 20223.95%−0.14
30 Jun 20224.09%+0.35
15 Jun 20223.74%−0.42
31 May 20224.16%−0.12
13 May 20224.28%+0.35
29 Apr 20223.93%−0.10
14 Apr 20224.03%−0.23
31 Mar 20224.26%+0.13
15 Mar 20224.13%−0.29
28 Feb 20224.42%+0.73
15 Feb 20223.69%−0.64
31 Jan 20224.33%+0.27
14 Jan 20224.06%+0.43
31 Dec 20213.63%−0.31
15 Dec 20213.94%+0.24
30 Nov 20213.70%+0.09
15 Nov 20213.61%−0.12
29 Oct 20213.73%−0.14
15 Oct 20213.87%+0.29
30 Sep 20213.58%+0.91
15 Sep 20212.67%−0.14
31 Aug 20212.81%+0.40
13 Aug 20212.41%–

Newest first. Scroll inside the table for earlier dates, back to 13 Aug 2021.

Frequently asked questions

How shorted is Quantum-Si Incorporated Class right now?
5.96% of Quantum-Si Incorporated Class's (QSI) shares outstanding were reported short for settlement date 15 Sep 2026, per FINRA's consolidated short interest report. That makes it the 1,393rd 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 QSI'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 QSI's days to cover?
10.32 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.