Skip to content
HowShorted

ACIU short interest Nasdaq Global Market

AC Immune SA Common Stock. FINRA's reported shares short for this symbol, twice a month by settlement date, shown as the regulator publishes them. No percentage is shown: an SEC filer exists but no defensible share count is available yet.

Shares short
3,475,472
vs previous settlement
+179,341 (+5.4%)
days to cover
25.00
Settlement date
15 Sep 2026

Shares short over time

Aggregate net short position time series for ACIU shares short

Days to cover

FINRA's own figure: reported shares short divided by the security's average daily trading volume, published alongside each settlement.

Aggregate net short position time series for ACIU 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 Common Stock 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.

History

Every FINRA settlement we hold for ACIU, newest first. สณ marks a figure FINRA itself flagged as revised.

Full reported short interest history
Settlement dateShares shortChangeDays to cover
15 Sep 20263,475,472+179,34125.00
31 Aug 20263,296,131โˆ’109,77614.99
14 Aug 20263,405,907โˆ’145,41514.29
31 Jul 20263,551,322+155,37318.18
15 Jul 20263,395,949+19,01713.27
30 Jun 20263,376,932โˆ’139,26012.99
15 Jun 20263,516,192+162,7219.60
29 May 20263,353,471+127,01816.31
15 May 20263,226,453+192,34010.12
30 Apr 20263,034,113+100,59012.91
15 Apr 20262,933,523โˆ’30,94410.01
31 Mar 20262,964,467โˆ’127,39214.59
13 Mar 20263,091,859โˆ’224,2829.28
27 Feb 20263,316,141+80,5789.42
13 Feb 20263,235,563โˆ’63,05713.09
30 Jan 20263,298,620+47,80610.69
15 Jan 20263,250,814โˆ’96,1136.27
31 Dec 20253,346,927โˆ’246,30010.55
15 Dec 20253,593,227+1,745,0631.63
28 Nov 20251,848,164+229,6558.02
14 Nov 20251,618,509+5,5696.99
31 Oct 20251,612,940+35,9413.61
15 Oct 20251,576,999โˆ’63,1213.55
30 Sep 20251,640,120+62,7669.72
15 Sep 20251,577,354+99,7348.83
29 Aug 20251,477,620โˆ’15,14916.89
15 Aug 20251,492,769+32811.56
31 Jul 20251,492,441+90,7488.21
15 Jul 20251,401,693โˆ’9,66211.36
30 Jun 20251,411,355+48,07211.82
13 Jun 20251,363,283โˆ’23,0429.95
30 May 20251,386,325โˆ’45,00213.83
15 May 20251,431,327+56,04012.91
30 Apr 20251,375,287โˆ’73,4568.91
15 Apr 20251,448,743+11,2456.78
31 Mar 20251,437,498+88,4367.75
14 Mar 20251,349,062+262,2476.64
28 Feb 20251,086,815โˆ’71,5576.11
14 Feb 20251,158,372+101,0035.09
31 Jan 20251,057,369+43,9237.01
15 Jan 20251,013,446+7,4217.79
31 Dec 20241,006,025+19,8977.08
13 Dec 2024986,128โˆ’36,9846.67
29 Nov 20241,023,112โˆ’31,13213.60
15 Nov 20241,054,244+69,7835.83
31 Oct 2024984,461+187,54211.31
15 Oct 2024796,919โˆ’63,92611.66
30 Sep 2024860,845+98,4687.13
13 Sep 2024762,377+6,34911.13
30 Aug 2024756,028โˆ’27,9468.30
15 Aug 2024783,974โˆ’154,3657.44
31 Jul 2024938,339โˆ’26,5963.96
15 Jul 2024964,935+233,8183.98
28 Jun 2024731,117โˆ’70,2542.90
14 Jun 2024801,371+22,1482.21
31 May 2024779,223โˆ’834,7841.70
15 May 20241,614,007+1,107,8351.00
30 Apr 2024506,172โˆ’3,1832.43
15 Apr 2024509,355โˆ’51,2342.14
28 Mar 2024560,589โˆ’22,3832.18
15 Mar 2024582,972โˆ’45,0355.15
29 Feb 2024628,007โˆ’40,0734.75
15 Feb 2024668,080+187,5285.14
31 Jan 2024480,552โˆ’78,7084.20
12 Jan 2024559,260โˆ’19,9633.92
29 Dec 2023579,223+82,8312.99
15 Dec 2023496,392โˆ’15,2932.59
30 Nov 2023511,685โˆ’53,19414.10
15 Nov 2023564,879+29,58112.41
31 Oct 2023535,298+50,17811.29
13 Oct 2023485,120+13,0239.80
29 Sep 2023472,097+17,08210.04
15 Sep 2023455,015+66,9877.43
31 Aug 2023388,028โˆ’36,5317.22
15 Aug 2023424,559โˆ’107,4836.52
31 Jul 2023532,042โˆ’221,2365.30
14 Jul 2023753,278โˆ’353,8283.48
30 Jun 20231,107,106+873,6061.00
15 Jun 2023233,500โˆ’2,1612.91
31 May 2023235,661โˆ’20,2855.05
15 May 2023255,946+22,1602.60
28 Apr 2023233,786โˆ’40,1373.56
14 Apr 2023273,923โˆ’16,2986.26
31 Mar 2023290,221โˆ’5,0361.94
15 Mar 2023295,257+8,9776.52
28 Feb 2023286,280โˆ’6,7345.39
15 Feb 2023293,014โˆ’23,7551.44
31 Jan 2023316,769+64,5571.33
13 Jan 2023252,212+9,0131.00
30 Dec 2022243,199โˆ’78,4571.00
15 Dec 2022321,656โˆ’14,4292.58
30 Nov 2022336,085โˆ’108,9633.55
15 Nov 2022445,048โˆ’10,0366.91
31 Oct 2022455,084โˆ’21,4247.43
14 Oct 2022476,508โˆ’13,0418.03
30 Sep 2022489,549+29,2494.36
15 Sep 2022460,300+84,58910.95
31 Aug 2022375,711โˆ’85,5968.18
15 Aug 2022461,307+47,05910.99
29 Jul 2022414,248โˆ’23,4116.81
15 Jul 2022437,659โˆ’50,81211.84
30 Jun 2022488,471+30,4302.59
15 Jun 2022458,041โˆ’26,0059.30
31 May 2022484,046โˆ’188,3103.96
13 May 2022672,356โˆ’165,9718.23
29 Apr 2022838,327โˆ’49,91212.30
14 Apr 2022888,239+180,99511.66
31 Mar 2022707,244โˆ’6,8556.72
15 Mar 2022714,099โˆ’27,4919.05
28 Feb 2022741,590+212,5555.73
15 Feb 2022529,035โˆ’13,5033.61
31 Jan 2022542,538โˆ’19,8493.55
14 Jan 2022562,387+23,6424.31
31 Dec 2021538,745+29,0062.56
15 Dec 2021509,739+4,4422.04
30 Nov 2021505,297โˆ’103,6201.38
15 Nov 2021608,917โˆ’632,7451.00
29 Oct 20211,241,662+171,3173.36
15 Oct 20211,070,345โˆ’133,6463.27
30 Sep 20211,203,991+70,7203.40
15 Sep 20211,133,271+95,5451.09
31 Aug 20211,037,726โˆ’136,2571.00
13 Aug 20211,173,983โˆ’45,1989.83
30 Jul 20211,219,181+10,9345.97
15 Jul 20211,208,247+87,7173.97
30 Jun 20211,120,530โˆ’166,8813.03
15 Jun 20211,287,411สณ+258,0921.00
28 May 20211,029,319โˆ’166,5233.08
14 May 20211,195,842โˆ’18,9057.86
30 Apr 20211,214,747โˆ’90,9898.51
15 Apr 20211,305,736โˆ’115,1897.26
31 Mar 20211,420,925โˆ’90,6095.20
15 Mar 20211,511,534+48,2284.46
26 Feb 20211,463,306+300,3881.48
12 Feb 20211,162,918+88,6631.00
29 Jan 20211,074,255โˆ’159,0454.73
15 Jan 20211,233,300โˆ’46,8412.62
31 Dec 20201,280,141โˆ’1,1413.19
15 Dec 20201,281,282โˆ’192,6334.83
30 Nov 20201,473,915โˆ’182,32710.94
13 Nov 20201,656,242โˆ’218,4513.45
30 Oct 20201,874,693+32,79811.60
15 Oct 20201,841,895โˆ’147,7275.82
30 Sep 20201,989,622+334,8392.11
15 Sep 20201,654,783+114,5856.97
31 Aug 20201,540,198โˆ’10,6776.47
14 Aug 20201,550,875+490,4594.41
31 Jul 20201,060,416+441,9741.00
15 Jul 2020618,442โˆ’8,66310.93
30 Jun 2020627,105+10,9129.35
15 Jun 2020616,193โˆ’50,6677.00
29 May 2020666,860+68,26711.36
15 May 2020598,593+7,8986.77
30 Apr 2020590,695+7,5957.06
15 Apr 2020583,100+42,9773.92
31 Mar 2020540,123+153,2203.18
13 Mar 2020386,903+21,9193.34
28 Feb 2020364,984+55,7792.44
14 Feb 2020309,205โˆ’137,4171.58
31 Jan 2020446,622สณโˆ’6,0774.84
15 Jan 2020452,699+46,4642.14
31 Dec 2019406,235โˆ’25,8122.68
13 Dec 2019432,047+26,4713.62
29 Nov 2019405,576โˆ’54,9602.85
15 Nov 2019460,536โˆ’30,8965.89
31 Oct 2019491,432+35,4966.22
15 Oct 2019455,936+64,8868.92
30 Sep 2019391,050โˆ’110,6423.86
13 Sep 2019501,692โˆ’42,3433.06
30 Aug 2019544,035โˆ’73,2615.69
15 Aug 2019617,296+16,7274.92
31 Jul 2019600,569+117,6738.05
15 Jul 2019482,896โˆ’132,0935.87
28 Jun 2019614,989+294,6618.15
14 Jun 2019320,328สณโˆ’24,6972.52
31 May 2019345,025โˆ’230,4782.34
15 May 2019575,503โˆ’8,9993.41
30 Apr 2019584,502โˆ’25,6554.52
15 Apr 2019610,157โˆ’97,7301.56
29 Mar 2019707,887โˆ’38,3051.19
15 Mar 2019746,192+54,8202.78
28 Feb 2019691,372โˆ’81,0531.65
15 Feb 2019772,425โˆ’960,1471.27
31 Jan 20191,732,572โˆ’30,8611.06
15 Jan 20191,763,433+51,1558.10
31 Dec 20181,712,278+291,2106.63
14 Dec 20181,421,068โˆ’5,39312.87
30 Nov 20181,426,461โˆ’11,90411.85
15 Nov 20181,438,365โˆ’6,23627.73
31 Oct 20181,444,601+145,92711.80
15 Oct 20181,298,674โˆ’25,0206.76
28 Sep 20181,323,694โˆ’27,8297.41
14 Sep 20181,351,523โˆ’54,89217.55
31 Aug 20181,406,415+12,2879.19
15 Aug 20181,394,128+103,45013.19
31 Jul 20181,290,678โˆ’240,8252.14
13 Jul 20181,531,503โˆ’77,6284.23
29 Jun 20181,609,131โˆ’48,57066.36
15 Jun 20181,657,701โˆ’9,13963.46
31 May 20181,666,840โˆ’36,254114.15
15 May 20181,703,094โˆ’5,673102.49
30 Apr 20181,708,767+44,44145.61
13 Apr 20181,664,326โˆ’41,53336.27
29 Mar 20181,705,859โˆ’90,47431.12
15 Mar 20181,796,333โˆ’1,87926.86
28 Feb 20181,798,212+52,69816.19
15 Feb 20181,745,514+4,31721.50
31 Jan 20181,741,197โˆ’20,99646.44
12 Jan 20181,762,193+98,23829.01
29 Dec 20171,663,955โ€“14.20

Scroll inside the table for earlier settlements, back to 29 Dec 2017.

Questions

Frequently asked questions

What is ACIU's short interest?
3,475,472 shares short for settlement date 15 Sep 2026, per FINRA's consolidated short interest report, up 179,341 from the previous settlement.
Why is there no percentage for ACIU?
Because no defensible share count exists to divide by: an SEC filer exists but no defensible share count is available yet. The symbol maps to an SEC filer, but its share count cannot be used yet. A newly listed company needs two cover-page counts on file before the first is trusted; a split or an unexplained jump pauses publication until a fresh SEC count corroborates it; a secondary share class publishes under the company's primary line; and a foreign filer's short count is in depositary-share units. This page upgrades to a percentage automatically once a defensible count exists.
What is ACIU's days to cover?
25.00 days for settlement date 15 Sep 2026: FINRA's own short interest ratio, the reported shares short divided by average daily trading volume, published in the same file and shown verbatim. We hold no volume data ourselves.
Is this the short float?
No. This page shows FINRA's share count only. Short float divides that count by the public float, and short interest as we publish it elsewhere divides it by shares outstanding from SEC filings. Neither denominator is available for this line, so neither ratio is shown.
How often does this update?
FINRA member firms report short positions as of the 15th and the last business day of each month, and FINRA publishes the consolidated figures about nine business days later. We ingest each file the day it appears and re-read recent settlements for revisions.

Ranked companies with a percentage: most shorted US stocks. Other symbols with counts only: shares short without a percentage. Browse by name: US companies A to Z.