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HowShorted

How shorted is AC Immune SA? ACIU

3.35%
of shares outstanding reported short · settlement date 14 Aug 2026
vs previous report
−0.14
5 reports (~10 weeks)
+0.05
days to cover
14.29
Aggregate net short position time series for AC Immune SA

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 AC Immune SA days to cover

Fails to deliver

The SEC's fails-to-deliver figure for ACIU: 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
1,913
14 Sep 2026
Highest in window
383,960
16 Dec 2025
Days with a balance
83
Window
16 Sep 2025 to 14 Sep 2026
Aggregate net short position time series for AC Immune SA 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 384K shares.

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Sector: Healthcare

History

Full reported short interest history
Settlement dateShort %Change
14 Aug 20263.35%−0.14
31 Jul 20263.49%+0.15
15 Jul 20263.34%+0.02
30 Jun 20263.32%−0.14
15 Jun 20263.46%+0.16
29 May 20263.30%+0.13
15 May 20263.17%+0.19
30 Apr 20262.98%+0.10
15 Apr 20262.88%−0.03
31 Mar 20262.91%−0.13
13 Mar 20263.04%−0.22
27 Feb 20263.26%+0.08
13 Feb 20263.18%−0.06
30 Jan 20263.24%+0.04
15 Jan 20263.20%−0.09
31 Dec 20253.29%+1.72
15 Sep 20251.57%+0.10
29 Aug 20251.47%−0.02
15 Aug 20251.49%0.00
31 Jul 20251.49%+0.09
15 Jul 20251.40%−0.01
30 Jun 20251.41%+0.05
13 Jun 20251.36%−0.02
30 May 20251.38%−0.05
15 May 20251.43%+0.06
30 Apr 20251.37%−0.07
15 Apr 20251.44%+0.01
31 Mar 20251.43%+0.09
14 Mar 20251.34%+0.26
28 Feb 20251.08%−0.07
14 Feb 20251.15%+0.10
31 Jan 20251.05%+0.04
15 Jan 20251.01%+0.01
31 Dec 20241.00%+0.23
13 Sep 20240.77%+0.01
30 Aug 20240.76%−0.03
15 Aug 20240.79%−0.16
31 Jul 20240.95%−0.02
15 Jul 20240.97%+0.23
28 Jun 20240.74%−0.07
14 Jun 20240.81%+0.02
31 May 20240.79%+0.28
30 Apr 20240.51%0.00
15 Apr 20240.51%−0.06
28 Mar 20240.57%−0.02
15 Mar 20240.59%−0.04
29 Feb 20240.63%−0.04
15 Feb 20240.67%+0.19
31 Jan 20240.48%−0.08
12 Jan 20240.56%+0.02
15 Sep 20230.54%+0.08
31 Aug 20230.46%−0.05
15 Aug 20230.51%−0.13
31 Jul 20230.64%+0.36
15 Jun 20230.28%0.00
31 May 20230.28%−0.03
15 May 20230.31%+0.03
28 Apr 20230.28%−0.05
14 Apr 20230.33%−0.02
31 Mar 20230.35%0.00
15 Mar 20230.35%+0.01
28 Feb 20230.34%−0.01
15 Feb 20230.35%−0.03
31 Jan 20230.38%+0.08
13 Jan 20230.30%−0.25
15 Sep 20220.55%+0.10
31 Aug 20220.45%−0.10
15 Aug 20220.55%+0.05
29 Jul 20220.50%−0.02
15 Jul 20220.52%−0.07
30 Jun 20220.59%+0.04
15 Jun 20220.55%−0.03
31 May 20220.58%−0.23
13 May 20220.81%−0.19
29 Apr 20221.00%−0.06
14 Apr 20221.06%+0.21
31 Mar 20220.85%−0.01
15 Mar 20220.86%−0.03
28 Feb 20220.89%+0.26
15 Feb 20220.63%−0.02
31 Jan 20220.65%−0.02
14 Jan 20220.67%+0.02
31 Dec 20210.65%−0.93
15 Sep 20211.58%+0.14
31 Aug 20211.44%−0.19
13 Aug 20211.63%−0.06
30 Jul 20211.69%+0.01
15 Jul 20211.68%+0.12
30 Jun 20211.56%−0.23
15 Jun 20211.79%+0.36
28 May 20211.43%−0.23
14 May 20211.66%−0.03
30 Apr 20211.69%−0.13
15 Apr 20211.82%−0.16
31 Mar 20211.98%−0.12
15 Mar 20212.10%+0.07
26 Feb 20212.03%+0.41
12 Feb 20211.62%+0.13
29 Jan 20211.49%−0.22
15 Jan 20211.71%−0.07
31 Dec 20201.78%−0.52
15 Sep 20202.30%+0.16
31 Aug 20202.14%−0.02
14 Aug 20202.16%+0.68
31 Jul 20201.48%+0.62
15 Jul 20200.86%−0.01
30 Jun 20200.87%+0.01
15 Jun 20200.86%−0.07
29 May 20200.93%+0.10
15 May 20200.83%+0.01
30 Apr 20200.82%+0.01
15 Apr 20200.81%+0.06
31 Mar 20200.75%+0.21
13 Mar 20200.54%+0.03
28 Feb 20200.51%+0.08
14 Feb 20200.43%−0.19
31 Jan 20200.62%−0.01
15 Jan 20200.63%+0.06
31 Dec 20190.57%–

Newest first. Scroll inside the table for earlier dates, back to 31 Dec 2019.

Frequently asked questions

How shorted is AC Immune SA right now?
3.35% of AC Immune SA's (ACIU) shares outstanding were reported short for settlement date 14 Aug 2026, per FINRA's consolidated short interest report.
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 ACIU'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 ACIU's days to cover?
14.29 days for settlement date 14 Aug 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.