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HowShorted

How shorted is REPLIGEN CORP? RGEN

#496most shorted US stockof 3,805 ranked stocks, more shorted than 86%

11.89%
of shares outstanding reported short · settlement date 15 Sep 2026
vs previous report
+0.17
5 reports (~10 weeks)
+1.17
days to cover
7.09
Aggregate net short position time series for REPLIGEN CORP

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 REPLIGEN CORP 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
28 Jul 202610.30% 15 Jul 202610.87% 31 Jul 2026+0.57
22 Jul 202610.30% 15 Jul 202610.87% 31 Jul 2026+0.57
5 May 20269.77% 30 Apr 202610.10% 15 May 2026+0.33
24 Feb 20267.19% 13 Feb 20267.11% 27 Feb 2026−0.08
28 Oct 20256.01% 15 Oct 20255.90% 31 Oct 2025−0.11
29 Jul 20256.05% 15 Jul 20256.48% 31 Jul 2025+0.43
29 Apr 20255.77% 15 Apr 20256.12% 30 Apr 2025+0.35
20 Feb 20255.79% 14 Feb 20256.16% 28 Feb 2025+0.37

Fails to deliver

The SEC's fails-to-deliver figure for RGEN: 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
321
11 Sep 2026
Highest in window
72,778
30 Jun 2026
Days with a balance
67
Window
16 Sep 2025 to 14 Sep 2026
Aggregate net short position time series for REPLIGEN CORP 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 73K shares.

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Sector: Healthcare

History

Full reported short interest history
Settlement dateShort %Change
15 Sep 202611.89%+0.17
31 Aug 202611.72%+0.94
14 Aug 202610.78%−0.09
31 Jul 202610.87%+0.57
15 Jul 202610.30%−0.42
30 Jun 202610.72%+0.57
15 Jun 202610.15%−0.42
29 May 202610.57%+0.47
15 May 202610.10%+0.33
30 Apr 20269.77%+0.02
15 Apr 20269.75%−0.12
31 Mar 20269.87%+2.16
13 Mar 20267.71%+0.60
27 Feb 20267.11%−0.08
13 Feb 20267.19%−0.01
30 Jan 20267.20%+0.23
15 Jan 20266.97%−0.02
31 Dec 20256.99%−0.33
15 Dec 20257.32%−0.34
28 Nov 20257.66%+0.40
14 Nov 20257.26%+1.36
31 Oct 20255.90%−0.11
15 Oct 20256.01%−0.06
30 Sep 20256.07%−0.23
15 Sep 20256.30%−0.14
29 Aug 20256.44%−0.49
15 Aug 20256.93%+0.45
31 Jul 20256.48%+0.43
15 Jul 20256.05%−0.66
30 Jun 20256.71%+0.67
13 Jun 20256.04%−0.10
30 May 20256.14%+0.09
15 May 20256.05%−0.07
30 Apr 20256.12%+0.35
15 Apr 20255.77%−0.54
31 Mar 20256.31%−0.45
14 Mar 20256.76%+0.60
28 Feb 20256.16%+0.37
14 Feb 20255.79%−0.11
31 Jan 20255.90%+0.12
15 Jan 20255.78%+0.12
31 Dec 20245.66%−0.04
13 Dec 20245.70%−0.19
29 Nov 20245.89%−0.22
15 Nov 20246.11%+0.22
31 Oct 20245.89%−0.29
15 Oct 20246.18%−0.61
30 Sep 20246.79%−0.21
13 Sep 20247.00%−0.23
30 Aug 20247.23%−0.63
15 Aug 20247.86%+0.02
31 Jul 20247.84%+0.27
15 Jul 20247.57%+0.03
28 Jun 20247.54%−0.06
14 Jun 20247.60%−0.15
31 May 20247.75%−0.04
15 May 20247.79%−0.12
30 Apr 20247.91%−0.31
15 Apr 20248.22%−0.32
28 Mar 20248.54%0.00
15 Mar 20248.54%−0.19
29 Feb 20248.73%−0.86
15 Feb 20249.59%−0.81
31 Jan 202410.40%−0.03
12 Jan 202410.43%−0.28
29 Dec 202310.71%−0.23
15 Dec 202310.94%+0.20
30 Nov 202310.74%0.00
15 Nov 202310.74%+0.05
31 Oct 202310.69%−0.03
13 Oct 202310.72%+0.23
29 Sep 202310.49%+0.61
15 Sep 20239.88%+0.12
31 Aug 20239.76%+0.07
15 Aug 20239.69%−0.17
31 Jul 20239.86%+0.17
14 Jul 20239.69%+0.10
30 Jun 20239.59%−0.91
15 Jun 202310.50%+0.52
31 May 20239.98%+0.46
15 May 20239.52%−0.12
28 Apr 20239.64%+0.88
14 Apr 20238.76%+0.73
31 Mar 20238.03%+0.58
15 Mar 20237.45%0.00
28 Feb 20237.45%+0.63
15 Feb 20236.82%−0.47
31 Jan 20237.29%−0.03
13 Jan 20237.32%+0.73
30 Dec 20226.59%+0.13
15 Dec 20226.46%+0.65
30 Nov 20225.81%−0.05
15 Nov 20225.86%+0.25
31 Oct 20225.61%+0.26
14 Oct 20225.35%+0.55
30 Sep 20224.80%+0.04
15 Sep 20224.76%+0.05
31 Aug 20224.71%−0.39
15 Aug 20225.10%−0.73
29 Jul 20225.83%+0.15
15 Jul 20225.68%+0.53
30 Jun 20225.15%+0.48
15 Jun 20224.67%−0.06
31 May 20224.73%+0.13
13 May 20224.60%−0.41
29 Apr 20225.01%+0.87
14 Apr 20224.14%+0.15
31 Mar 20223.99%−0.45
15 Mar 20224.44%+0.21
28 Feb 20224.23%+0.37
15 Feb 20223.86%+0.08
31 Jan 20223.78%+0.86
14 Jan 20222.92%+0.20
31 Dec 20212.72%−0.29
15 Dec 20213.01%−0.18
30 Nov 20213.19%+0.21
15 Nov 20212.98%+0.11
29 Oct 20212.87%−0.09
15 Oct 20212.96%−0.09
30 Sep 20213.05%+0.14
15 Sep 20212.91%+0.05
31 Aug 20212.86%−0.12
13 Aug 20212.98%−0.15
30 Jul 20213.13%+0.23
15 Jul 20212.90%−0.20
30 Jun 20213.10%−0.02
15 Jun 20213.12%−0.04
28 May 20213.16%+0.15
14 May 20213.01%+0.16
30 Apr 20212.85%−0.22
15 Apr 20213.07%+0.13
31 Mar 20212.94%+0.27
15 Mar 20212.67%+0.10
26 Feb 20212.57%−0.12
12 Feb 20212.69%+0.20
29 Jan 20212.49%+0.17
15 Jan 20212.32%−0.23
31 Dec 20202.55%−0.08
15 Dec 20202.63%−0.30
30 Nov 20202.93%−0.18
13 Nov 20203.11%+0.34
30 Oct 20202.77%−0.04
15 Oct 20202.81%+0.26
30 Sep 20202.55%−0.16
15 Sep 20202.71%−0.02
31 Aug 20202.73%+0.18
14 Aug 20202.55%−0.79
31 Jul 20203.34%+0.07
15 Jul 20203.27%+0.26
30 Jun 20203.01%−0.40
15 Jun 20203.41%−0.32
29 May 20203.73%−0.28
15 May 20204.01%−0.83
30 Apr 20204.84%−0.90
15 Apr 20205.74%+0.52
31 Mar 20205.22%+0.15
13 Mar 20205.07%+1.13
28 Feb 20203.94%−0.08
14 Feb 20204.02%−0.54
31 Jan 20204.56%−0.16
15 Jan 20204.72%+0.07
31 Dec 20194.65%−1.94
13 Dec 20196.59%+0.15
29 Nov 20196.44%−0.28
15 Nov 20196.72%+0.39
31 Oct 20196.33%−1.06
15 Oct 20197.39%+0.19
30 Sep 20197.20%+0.17
13 Sep 20197.03%−0.54
30 Aug 20197.57%−0.61
15 Aug 20198.18%−0.39
31 Jul 20198.57%−1.60
15 Jul 201910.17%+0.65
28 Jun 20199.52%+0.05
14 Jun 20199.47%+1.28
31 May 20198.19%+0.36
15 May 20197.83%−1.15
30 Apr 20198.98%+0.62
15 Apr 20198.36%−0.26
29 Mar 20198.62%−0.56
15 Mar 20199.18%−0.01
28 Feb 20199.19%−0.01
15 Feb 20199.20%+0.12
31 Jan 20199.08%+0.10
15 Jan 20198.98%−0.45
31 Dec 20189.43%−0.70
14 Dec 201810.13%−0.82
30 Nov 201810.95%−0.33
15 Nov 201811.28%−1.28
31 Oct 201812.56%−0.17
15 Oct 201812.73%+0.35
28 Sep 201812.38%+0.40
14 Sep 201811.98%+0.31
31 Aug 201811.67%+1.27
15 Aug 201810.40%−0.18
31 Jul 201810.58%+0.30
13 Jul 201810.28%−1.12
29 Jun 201811.40%+1.11
15 Jun 201810.29%+0.04
31 May 201810.25%−0.43
15 May 201810.68%−0.91
30 Apr 201811.59%+0.21
13 Apr 201811.38%+0.97
29 Mar 201810.41%−0.12
15 Mar 201810.53%+0.36
28 Feb 201810.17%+0.93
15 Feb 20189.24%−0.02
31 Jan 20189.26%−0.42
12 Jan 20189.68%+0.44
29 Dec 20179.24%–

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

Frequently asked questions

How shorted is REPLIGEN CORP right now?
11.89% of REPLIGEN CORP's (RGEN) shares outstanding were reported short for settlement date 15 Sep 2026, per FINRA's consolidated short interest report. That makes it the 496th 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 RGEN'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 RGEN's days to cover?
7.09 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.