Short interest // FINRA, biweekly, dated

RPID short interest

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Rapid Micro Biosystems, Inc. C

1.84% of RPID’s shares outstanding is sold short

888,578 shares short / 48,346,663 shares outstanding (share count as of 2026-06-30, 10-Q).

“Low” describes how crowded the short position is, not where the stock goes next. Percent of shares outstanding, not percent of float; where filings allow it, the float version appears below as a floor.

As of the 2026-10-15 settlement, which is 26 days ago. FINRA publishes twice a month on the seventh business day after settlement, so this cycle was published around 2026-10-26 and the next is expected around 2026-11-10. No free source anywhere has anything fresher, including sites that display this number next to a live price.

Shares sold short	888,578 ⊙ EVIDENCE — filed/published fact SourceFINRA consolidated short interest FieldcurrentShortPositionQuantity As of2026-10-15 settlement HowFile shrt20261015.csv in FINRA's catalog (posted ~7 business days after settlement). Open the source document →
Prior settlement	853,972
Change	+4.1%
Days to coverShares short divided by average daily volume, both FINRA figures.	3.83 ⊙ INFERENCE — derived by arithmetic SourceFINRA consolidated short interest FieldcurrentShortPositionQuantity ÷ averageDailyVolumeQuantity As of2026-10-15 settlement HowComputed from FINRA’s two published operands. FINRA’s own daysToCoverQuantity field floors at 1.00 and is not used. Open the source document →
Average daily volume (FINRA, the days-to-cover denominator)	232,114
Exchange	Nasdaq (SmallCap)
Reg SHO threshold listPersistent settlement failures under Reg SHO Rule 203. A delivery-failure list, not a “naked shorting” list.	Not on the list (2026-11-09)
Short interest, % of shares outstandingPercent of shares outstanding. Not percent of float, and the two are not the same number.	1.84%
Shares outstandingfrom filings, as of 2026-06-30	48,346,663

Short interest history

77 settlements on record, oldest 2023-08-15. Biweekly points, from FINRA’s own archive.

Dashed line at the 15 September 2026 settlement: FINRA began quoting every field of its short interest file. What it did to this history, and what we did

Settlement	Shares short	Change	% of shares out	Days to cover	Close, USD	Value short, USD
2026-10-15	888,578	+4.1%	no share count within 200 days	3.83	0.85	750,937
2026-09-30	853,972	-9.2%	no share count within 200 days	2.28	1.03	879,591
2026-09-15	940,376	+8.2%	no share count within 200 days	3.73	1.15	1.1M
2026-08-31	869,421	+3.0%	no share count within 200 days	4.48	1.52	1.3M
2026-08-14	843,821	+2.2%	no share count within 200 days	2.99	1.68	1.4M
2026-07-31	825,765	-2.0%	no share count within 200 days	5.05	2.13	1.8M
2026-07-15	842,336	+14.1%	no share count within 200 days	3.19	2.21	1.9M
2026-06-30	738,469	+20.3%	no share count within 200 days	3.70	1.73	1.3M
2026-06-15	613,997	-18.0%	no share count within 200 days	4.86	1.72	1.1M
2026-05-29	748,445	+13.4%	no share count within 200 days	3.91	2.01	1.5M
2026-05-15	659,825	-18.4%	no share count within 200 days	5.16	2.07	1.4M
2026-04-30	808,896	+48.7%	no share count within 200 days	4.18	2.40	1.9M

Show the other 65 settlements, back to 2023-08-15

Settlement	Shares short	Change	% of shares out	Days to cover	Close, USD	Value short, USD
2026-04-15	543,866	+44.1%	no share count within 200 days	2.94	2.35	1.3M
2026-03-31	377,502	+18.9%	no share count within 200 days	1.36	2.27	856,930
2026-03-13	317,445	+46.4%	no share count within 200 days	1.35	2.83	898,369
2026-02-27	216,880	+22.1%	no share count within 200 days	2.16	4.33	939,090
2026-02-13	177,566	+6.9%	no share count within 200 days	0.79	3.91	694,283
2026-01-30	166,073	-7.0%	no share count within 200 days	0.39	4.43	735,703
2026-01-15	178,556	-0.2%	no share count within 200 days	0.50	3.45	616,018
2025-12-31	178,907	+10.9%	no share count within 200 days	1.22	2.90	518,830
2025-12-15	161,309	-32.4%	no share count within 200 days	1.52	3.47	559,742
2025-11-28	238,781	-20.8%	no share count within 200 days	2.35	4.19	1.0M
2025-11-14	301,487	-3.0%	no share count within 200 days	1.87	4.21	1.3M
2025-10-31	310,680	-3.7%	no share count within 200 days	3.78	2.99	928,933
2025-10-15	322,737	-14.7%	no share count within 200 days	3.47	3.18	1.0M
2025-09-30	378,496	-1.6%	no share count within 200 days	6.31	3.34	1.3M
2025-09-15	384,672	+12.9%	no share count within 200 days	4.57	3.15	1.2M
2025-08-29	340,630	+0.7%	no share count within 200 days	5.70	2.41	820,918
2025-08-15	338,113	-1.9%	no share count within 200 days	2.71	2.62	885,856
2025-07-31	344,774	-15.8%	no share count within 200 days	3.09	3.33	1.1M
2025-07-15	409,487	-20.6%	no share count within 200 days	6.01	3.26	1.3M
2025-06-30	515,575	-25.1%	no share count within 200 days	5.95	3.45	1.8M
2025-06-13	687,965	-6.7%	no share count within 200 days	8.07	3.55	2.4M
2025-05-30	737,522	-25.1%	no share count within 200 days	7.59	3.33	2.5M
2025-05-15	985,243	-29.9%	no share count within 200 days	4.65	3.06	3.0M
2025-04-30	1,406,279	-2.6%	no share count within 200 days	14.29	2.32	3.3M
2025-04-15	1,443,941	-10.1%	no share count within 200 days	8.49	2.28	3.3M
2025-03-31	1,605,753	+35.6%	no share count within 200 days	8.42	2.64	4.2M
2025-03-14	1,184,306	+191.4%	no share count within 200 days	2.26	2.46	2.9M
2025-02-28	406,473	+202.3%	no share count within 200 days	0.28	3.05	1.2M
2025-02-14	134,447	+1.6%	no share count within 200 days	0.20	3.48	467,876
2025-01-31	132,346	+16.5%	no share count within 200 days	0.45	1.79	236,899
2025-01-15	113,587	+160.6%	no share count within 200 days	0.67	1.26	143,688
2024-12-31	43,583	-25.1%	no share count within 200 days	0.60	0.90	39,225
2024-12-13	58,189	+86.9%	no share count within 200 days	1.53	1.00	58,206
2024-11-29	31,130	-29.3%	no share count within 200 days	0.48	1.04	32,531
2024-11-15	44,049	-37.5%	no share count within 200 days	0.51	1.04	45,811
2024-10-31	70,423	+299.7%	no share count within 200 days	0.53	1.08	76,057
2024-10-15	17,621	-55.9%	no share count within 200 days	1.01	0.88	15,505
2024-09-30	39,921	-43.2%	no share count within 200 days	0.59	0.89	35,530
2024-09-13	70,246	+55.0%	no share count within 200 days	2.02	0.83	58,655
2024-08-30	45,329	-43.1%	no share count within 200 days	0.69	0.85	38,525
2024-08-15	79,619	+591.4%	no share count within 200 days	0.61	0.83	66,132
2024-07-31	11,516	-45.2%	no share count within 200 days	0.46	0.66	7,612
2024-07-15	21,004	-40.8%	no share count within 200 days	0.91	0.65	13,695
2024-06-28	35,476	+31.9%	no share count within 200 days	0.94	before stored bars	no close to value it
2024-06-14	26,903	+38.1%	no share count within 200 days	1.44	before stored bars	no close to value it
2024-05-31	19,483	-49.7%	no share count within 200 days	1.04	before stored bars	no close to value it
2024-05-15	38,768	-27.1%	no share count within 200 days	0.52	before stored bars	no close to value it
2024-04-30	53,215	-12.6%	no share count within 200 days	1.88	before stored bars	no close to value it
2024-04-15	60,883	+5.1%	no share count within 200 days	1.67	before stored bars	no close to value it
2024-03-28	57,908	-27.9%	no share count within 200 days	1.52	before stored bars	no close to value it
2024-03-15	80,341	-10.9%	no share count within 200 days	1.51	before stored bars	no close to value it
2024-02-29	90,151	-13.1%	no share count within 200 days	2.14	before stored bars	no close to value it
2024-02-15	103,682	-21.4%	no share count within 200 days	2.34	before stored bars	no close to value it
2024-01-31	131,862	-21.7%	no share count within 200 days	1.33	before stored bars	no close to value it
2024-01-12	168,473	+341.9%	no share count within 200 days	0.17	before stored bars	no close to value it
2023-12-29	38,129	+152.0%	no share count within 200 days	0.17	before stored bars	no close to value it
2023-12-15	15,130	+66.0%	no share count within 200 days	0.96	before stored bars	no close to value it
2023-11-30	9,117	+34.5%	no share count within 200 days	0.65	before stored bars	no close to value it
2023-11-15	6,779	-16.2%	no share count within 200 days	0.46	before stored bars	no close to value it
2023-10-31	8,091	-35.0%	no share count within 200 days	0.42	before stored bars	no close to value it
2023-10-13	12,446	-35.4%	no share count within 200 days	0.39	before stored bars	no close to value it
2023-09-29	19,262	-26.1%	no share count within 200 days	0.96	before stored bars	no close to value it
2023-09-15	26,067	+6.1%	no share count within 200 days	0.56	before stored bars	no close to value it
2023-08-31	24,576	-4.4%	no share count within 200 days	1.48	before stored bars	no close to value it
2023-08-15	25,695	no prior settlement	no share count within 200 days	0.73	before stored bars	no close to value it

Change is against the settlement before it, and is left out where one is missing from the archive. Percent of shares outstanding divides by the filed share count dated nearest each settlement, within 200 days, so it moves when the share count does; it is not percent of float. Close and value short (shares short times that day’s close, both as traded) come from our stored daily bars, which begin 2024-07-01; earlier settlements show none rather than a figure from another source. Nothing here is split-adjusted, so a split appears as the step it was.

Different measurement // daily, and not a position

Daily short volume

This is not the number above. Short interest is the position still held short, reported twice a month. Short volume is the share of a single day’s trading that was marked as a sell-short order, published daily. Most of it is market makers hedging and closing within the same session, so a stock printing a high figure here is not that percentage sold short.

Latest session (2026-11-09)

61.4%

Average, last 10 sessions

46.1%

2026-11-0961.4%

2026-11-0636.7%

2026-11-0557.4%

2026-11-0468.1%

2026-11-0348.4%

2026-11-0235.1%

2026-10-3023.5%

2026-10-2951.4%

2026-10-2850.3%

2026-10-2728.6%

FINRA Reg SHO consolidated daily file. Sessions with no row for RPID are omitted rather than shown as zero.

Price context // daily bars, not short data

Where the price sits

Session of 2026-11-09, from 276 sessions of daily bars. These are price figures, not short figures, and they update daily rather than twice a month.

Close	$0.73
Volume, latest session	532,341
Volume vs averageAgainst its own 50-session average of 241,566, same series on both sides	2.20x
% from 52-week high ($4.94)	-85.2%
% from 52-week low ($0.58)	+25.8%
52-week performance	-77.5%
% from 50-day average ($0.98)	-25.4%
% from 200-day average ($2.13)	-65.8%
RSI, 14-dayWilder’s construction, so it matches what charting platforms print	38.9

Why there is no “% of float” here

Percent of float is the number the paid trackers lead with, and it is the one number in this category that cannot be published honestly for free. There is no free float share count: the SEC’s XBRL concept for float does not exist, and the closest one, public float, is measured in dollars and is filed once a year with the annual report. For Apple it currently reads as of March 2025, sixteen months ago.

So a free site showing percent of float is doing one of two things: quietly substituting shares outstanding, which for a heavily insider-held small company is a wildly different number, or republishing a commercial estimate it licensed. We publish the percentage that filed data supports, label it as percent of shares outstanding, and where insider Form 4 filings allow it we publish percent of float as an explicit floor: subtracting only filed direct insider holdings from shares outstanding gives a ceiling on float, so the division gives a number the true percentage can only exceed. What we will not do is print a bare “% of float” built on someone else’s estimate. Where a figure is measured, this site says what it was measured against. Read the methodology.

What days to cover means

Open short interest divided by average daily trading volume: roughly how many full sessions of normal volume it would take for every short position to be bought back. FINRA computes it per security at each settlement and we pass their figure through. This matters more than it sounds, because sites that compute their own pick their own volume window and rarely say which, so the same stock shows materially different values depending on where you look.

High short interest and high days to cover describe fuel, not ignition. They say a crowded position exists; they say nothing about whether it unwinds, and heavily shorted stocks frequently keep falling. Educational information, not investment advice.

FINRA is the owner and source of this short interest and short sale volume data. Free on every plan; not for redistribution.

RPID short interest FAQ

How old is this RPID short interest figure?

It is the 2026-10-15 settlement, which is 26 days ago. FINRA collects short interest twice a month and publishes on the seventh business day after each settlement date, so this was published around 2026-10-26 and the next cycle is expected around 2026-11-10. There is no fresher short interest available anywhere for free, including from tools that display it next to a live price.

Why does this show percent of shares outstanding rather than percent of float?

Because float share counts are not published by any free source. The SEC XBRL concept for float does not exist, and the nearest one is measured in dollars and comes only from the annual report. Every free site showing a float percentage is republishing a commercial estimate. We publish the percentage we can compute from filed data and label it for what it is, rather than passing shares outstanding off as float.

Where does days to cover come from?

Shares short divided by average daily volume, using FINRA’s own two published figures. We do not use FINRA’s own days-to-cover field, because it is floored at 1.00: across the current file, 7,869 securities, over a third of the market, are published at exactly 1.00 and nearly all of them are genuinely below it. One stock with a true ratio of 0.03 is published as 1.00. Sites that instead invent their own average-volume window produce a different problem, which is why the operands here are both FINRA’s.

Is high short interest a buy signal?

No. High short interest is frequently the market pricing real problems, and many heavily shorted stocks keep falling. This page measures positioning. It makes no recommendation.

Keep going: the full RPID workspace · short squeeze screener · RPID dilution profile · RPID off-exchange (ATS) volume · what short interest means · methodology