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HowShorted

How shorted is Alnylam Pharmaceuticals, Inc.? ALNY

#1,561most shorted US stockof 3,805 ranked stocks, more shorted than 58%

5.38%
of shares outstanding reported short · settlement date 15 Sep 2026
vs previous report
+0.64
5 reports (~10 weeks)
+1.01
days to cover
4.13
Aggregate net short position time series for Alnylam Pharmaceuticals, 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 Alnylam Pharmaceuticals, 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
30 Jul 20264.35% 15 Jul 20263.59% 31 Jul 2026−0.76
30 Apr 20263.80% 15 Apr 20264.07% 15 May 2026+0.27
12 Feb 20264.00% 30 Jan 20263.95% 13 Feb 2026−0.05
12 Jan 20264.19% 31 Dec 20254.21% 15 Jan 2026+0.02
30 Oct 20253.05% 15 Oct 20252.85% 31 Oct 2025−0.20
31 Jul 20252.59% 15 Jul 20252.61% 15 Aug 2025+0.02
13 Jan 20252.59% 31 Dec 20242.44% 15 Jan 2025−0.15
15 Feb 20243.19% 31 Jan 20242.41% 29 Feb 2024−0.78

Fails to deliver

The SEC's fails-to-deliver figure for ALNY: 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
3
26 Aug 2026
Highest in window
22,234
12 Jun 2026
Days with a balance
63
Window
16 Sep 2025 to 14 Sep 2026
Aggregate net short position time series for Alnylam Pharmaceuticals, 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 22K shares.

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Sector: Healthcare

History

Full reported short interest history
Settlement dateShort %Change
15 Sep 20265.38%+0.64
31 Aug 20264.74%+1.17
14 Aug 20263.57%−0.02
31 Jul 20263.59%−0.76
15 Jul 20264.35%−0.02
30 Jun 20264.37%+0.27
15 Jun 20264.10%+0.10
29 May 20264.00%−0.07
15 May 20264.07%+0.47
30 Apr 20263.60%−0.20
15 Apr 20263.80%−0.01
31 Mar 20263.81%+0.52
13 Mar 20263.29%−0.16
27 Feb 20263.45%−0.50
13 Feb 20263.95%−0.05
30 Jan 20264.00%−0.21
15 Jan 20264.21%+0.02
31 Dec 20254.19%+1.02
15 Dec 20253.17%+0.17
28 Nov 20253.00%−0.24
14 Nov 20253.24%+0.39
31 Oct 20252.85%−0.20
15 Oct 20253.05%+0.37
30 Sep 20252.68%−0.16
15 Sep 20252.84%−0.19
29 Aug 20253.03%+0.42
15 Aug 20252.61%+0.14
31 Jul 20252.47%−0.12
15 Jul 20252.59%+0.04
30 Jun 20252.55%−0.04
13 Jun 20252.59%−0.06
30 May 20252.65%−0.17
15 May 20252.82%+0.40
30 Apr 20252.42%+0.06
15 Apr 20252.36%+0.05
31 Mar 20252.31%+0.35
14 Mar 20251.96%+0.03
28 Feb 20251.93%−0.56
14 Feb 20252.49%+0.21
31 Jan 20252.28%−0.16
15 Jan 20252.44%−0.15
31 Dec 20242.59%−0.12
13 Dec 20242.71%+0.08
29 Nov 20242.63%−0.27
15 Nov 20242.90%+0.03
31 Oct 20242.87%−0.90
15 Oct 20243.77%+0.26
30 Sep 20243.51%+0.04
13 Sep 20243.47%+0.53
30 Aug 20242.94%−0.58
15 Aug 20243.52%+0.15
31 Jul 20243.37%−0.18
15 Jul 20243.55%+0.64
28 Jun 20242.91%+1.23
14 Jun 20241.68%−0.28
31 May 20241.96%−0.05
15 May 20242.01%−0.07
30 Apr 20242.08%+0.09
15 Apr 20241.99%−0.23
28 Mar 20242.22%+0.09
15 Mar 20242.13%−0.28
29 Feb 20242.41%−0.76
15 Feb 20243.17%−0.02
31 Jan 20243.19%−0.26
12 Jan 20243.45%−0.32
29 Dec 20233.77%−0.21
15 Dec 20233.98%−0.07
30 Nov 20234.05%−0.09
15 Nov 20234.14%−0.06
31 Oct 20234.20%−0.08
13 Oct 20234.28%+0.15
29 Sep 20234.13%+0.01
15 Sep 20234.12%−0.12
31 Aug 20234.24%−0.06
15 Aug 20234.30%+0.07
31 Jul 20234.23%+0.25
14 Jul 20233.98%−0.02
30 Jun 20234.00%+0.02
15 Jun 20233.98%−0.08
31 May 20234.06%−0.05
15 May 20234.11%+0.03
28 Apr 20234.08%+0.04
14 Apr 20234.04%−0.17
31 Mar 20234.21%+0.20
15 Mar 20234.01%−0.37
28 Feb 20234.38%+0.23
15 Feb 20234.15%−0.18
31 Jan 20234.33%−0.29
13 Jan 20234.62%+0.46
30 Dec 20224.16%−0.23
15 Dec 20224.39%+0.33
30 Nov 20224.06%−0.46
15 Nov 20224.52%−0.38
31 Oct 20224.90%+0.90
14 Oct 20224.00%+0.22
30 Sep 20223.78%+0.13
15 Sep 20223.65%+0.15
31 Aug 20223.50%−0.66
15 Aug 20224.16%+0.05
29 Jul 20224.11%−0.02
15 Jul 20224.13%+0.16
30 Jun 20223.97%+0.05
15 Jun 20223.92%−0.74
31 May 20224.66%−0.19
13 May 20224.85%−0.05
29 Apr 20224.90%+0.09
14 Apr 20224.81%+0.50
31 Mar 20224.31%+0.37
15 Mar 20223.94%+0.15
28 Feb 20223.79%+0.13
15 Feb 20223.66%+0.26
31 Jan 20223.40%+0.10
14 Jan 20223.30%+0.35
31 Dec 20212.95%−0.19
15 Dec 20213.14%−0.16
30 Nov 20213.30%−0.09
15 Nov 20213.39%+0.16
29 Oct 20213.23%−0.04
15 Oct 20213.27%−0.10
30 Sep 20213.37%−0.35
15 Sep 20213.72%−0.34
31 Aug 20214.06%−0.15
13 Aug 20214.21%−0.05
30 Jul 20214.26%+0.67
15 Jul 20213.59%−0.09
30 Jun 20213.68%−0.26
15 Jun 20213.94%+0.33
28 May 20213.61%−0.24
14 May 20213.85%+0.34
30 Apr 20213.51%0.00
15 Apr 20213.51%+0.39
31 Mar 20213.12%−0.06
15 Mar 20213.18%+0.02
26 Feb 20213.16%+0.15
12 Feb 20213.01%−0.17
29 Jan 20213.18%−0.15
15 Jan 20213.33%+0.33
31 Dec 20203.00%−0.15
15 Dec 20203.15%−0.11
30 Nov 20203.26%+0.05
13 Nov 20203.21%+0.12
30 Oct 20203.09%+0.17
15 Oct 20202.92%+0.11
30 Sep 20202.81%−0.28
15 Sep 20203.09%−0.38
31 Aug 20203.47%−0.21
14 Aug 20203.68%0.00
31 Jul 20203.68%−0.44
15 Jul 20204.12%−0.62
30 Jun 20204.74%−0.36
15 Jun 20205.10%+0.54
29 May 20204.56%+0.03
15 May 20204.53%+0.10
30 Apr 20204.43%−0.32
15 Apr 20204.75%+0.39
31 Mar 20204.36%+0.05
13 Mar 20204.31%−0.21
28 Feb 20204.52%+0.01
14 Feb 20204.51%+0.01
31 Jan 20204.50%+0.19
15 Jan 20204.31%+0.34
31 Dec 20193.97%−0.46
13 Dec 20194.43%−0.53
29 Nov 20194.96%−0.68
15 Nov 20195.64%−0.13
31 Oct 20195.77%+0.01
15 Oct 20195.76%+0.10
30 Sep 20195.66%+0.12
13 Sep 20195.54%+0.05
30 Aug 20195.49%+0.20
15 Aug 20195.29%+0.13
31 Jul 20195.16%+0.15
15 Jul 20195.01%+0.34
28 Jun 20194.67%−0.15
14 Jun 20194.82%−0.24
31 May 20195.06%+0.34
15 May 20194.72%−0.71
30 Apr 20195.43%+0.24
15 Apr 20195.19%+0.15
29 Mar 20195.04%−0.40
15 Mar 20195.44%+0.56
28 Feb 20194.88%−0.23
15 Feb 20195.11%−0.30
31 Jan 20195.41%−0.90
15 Jan 20196.31%+0.03
31 Dec 20186.28%+0.10
14 Dec 20186.18%+0.45
30 Nov 20185.73%+0.09
15 Nov 20185.64%−0.66
31 Oct 20186.30%+0.52
15 Oct 20185.78%−0.20
28 Sep 20185.98%+0.07
14 Sep 20185.91%−0.03
31 Aug 20185.94%+0.55
15 Aug 20185.39%+0.41
31 Jul 20184.98%−0.09
13 Jul 20185.07%−0.11
29 Jun 20185.18%+0.07
15 Jun 20185.11%+0.14
31 May 20184.97%−0.74
15 May 20185.71%0.00
30 Apr 20185.71%−0.03
13 Apr 20185.74%+0.99
29 Mar 20184.75%−0.07
15 Mar 20184.82%−0.07
28 Feb 20184.89%+0.11
15 Feb 20184.78%−0.32
31 Jan 20185.10%−1.24
12 Jan 20186.34%+0.10
29 Dec 20176.24%–

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

Frequently asked questions

How shorted is Alnylam Pharmaceuticals, Inc. right now?
5.38% of Alnylam Pharmaceuticals, Inc.'s (ALNY) shares outstanding were reported short for settlement date 15 Sep 2026, per FINRA's consolidated short interest report. That makes it the 1,561st 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 ALNY'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 ALNY's days to cover?
4.13 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.