Atrium Therapeutics (RNA)

Atrium Therapeutics on one page: short interest, daily short volume, fails to deliver, large holders, 13F holders, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as pharmaceutical preparations.

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3.7M

Short interest

settlement 2026-10-15

12.9

Days to cover

+4.7 days vs prior

62.1%

Short share of volume

2026-11-02

706

Fails to deliver

settlement 2026-09-18

Thu 13 May

Next earnings

estimated date

Insider flow, 90 days

0 buys, 0 sells

As of 2026-11-02.

Short interest

FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSON

As of 15 October 2026, short interest in RNA is 3,726,302 shares, up 328,511 shares over the last month. Over the last 48 readings it ranged from 432,798 shares (27 February 2026) to 22,242,546 shares (15 September 2025). At the reported average volume of 288K shares a day that is 12.9 days to cover.

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Settlement	Shares short	Change	Avg daily volume	Days to cover
2026-10-15	3,726,302	+9.7%	288,048	12.94
2026-09-30	3,395,873	-0.1%	410,851	8.27
2026-09-15	3,397,791	+1.4%	417,130	8.15
2026-08-31	3,351,526	-3.7%	169,372	19.79
2026-08-14	3,480,849	-0.9%	126,745	27.46
2026-07-31	3,514,133	-2.1%	123,798	28.39
2026-07-15	3,591,224	-1.8%	202,748	17.71
2026-06-30	3,656,821	+1.3%	292,054	12.52
2026-06-15	3,610,418	-1.2%	177,756	20.31
2026-05-29	3,653,605	-2.1%	230,736	15.83
2026-05-15	3,732,204	+8.9%	176,203	21.18
2026-04-30	3,425,955	+13.6%	393,381	8.71
2026-04-15	3,016,880	+57.6%	502,487	6.00
2026-03-31	1,913,700	+61.5%	659,361	2.90
2026-03-13	1,184,615	+173.7%	1,401,988	1.00
2026-02-27	432,798	+100.0%	731,579	1.00
2026-02-13	10,156,722	+16.1%	2,853,751	3.56
2026-01-30	8,745,197	+4.0%	1,377,968	6.35
2026-01-15	8,406,349	-4.4%	1,999,340	4.20
2025-12-31	8,791,796	-9.7%	1,907,860	4.61
2025-12-15	9,740,063	+9.9%	2,363,887	4.12
2025-11-28	8,865,578	-14.1%	2,676,349	3.31
2025-11-14	10,321,719	-1.7%	5,092,006	2.03
2025-10-31	10,497,758	-47.6%	12,878,301	1.00
2025-10-15	20,028,193	-3.5%	1,483,734	13.50
2025-09-30	20,751,004	-6.7%	2,835,828	7.32
2025-09-15	22,242,546	+26.6%	5,288,970	4.21
2025-08-29	17,571,891	+12.1%	1,960,429	8.96
2025-08-15	15,671,917	-3.3%	4,514,288	3.47
2025-07-31	16,212,032	-0.3%	2,860,120	5.67
2025-07-15	16,259,911	-2.8%	2,370,200	6.86
2025-06-30	16,722,117	+2.3%	1,142,516	14.64
2025-06-13	16,344,285	+1.1%	1,777,443	9.20
2025-05-30	16,174,977	+2.5%	1,085,271	14.90
2025-05-15	15,787,027	+1.3%	1,568,200	10.07
2025-04-30	15,584,357	+0.7%	1,173,212	13.28
2025-04-15	15,483,940	-11.9%	2,118,751	7.31
2025-03-31	17,574,901	+9.0%	1,532,018	11.47
2025-03-14	16,128,099	-4.9%	1,283,034	12.57
2025-02-28	16,954,734	+2.9%	1,264,375	13.41
2025-02-14	16,480,495	+10.2%	1,448,815	11.38
2025-01-31	14,949,939	-2.9%	1,246,050	12.00
2025-01-15	15,389,142	-1.9%	1,361,836	11.30
2024-12-31	15,684,175	+1.3%	1,416,793	11.07
2024-12-13	15,476,155	+3.6%	1,273,473	12.15
2024-11-29	14,935,394	+2.9%	908,207	16.44
2024-11-15	14,516,927	-1.0%	1,396,596	10.39
2024-10-31	14,659,552	-1.5%	734,650	19.95

Daily short volume

FINRA Reg SHO, the last 30 sessions. JSON

As of 2 November 2026, the short share of RNA volume is 62.1%, up 13.0 points over the last five sessions. Over the last 30 readings it ranged from 15.6% (30 October 2026) to 66.5% (14 October 2026). The latest reading sits at the top of that range. The latest reading is 21.1 points above the 30-session average of 41.0%, on 121K shares reported.

Date	Short volume	Total volume	Short share	Exempt
2026-11-02	75K	121K	62.1%	0
2026-10-30	30K	190K	15.6%	131
2026-10-29	15K	46K	33.5%	0
2026-10-28	15K	70K	21.2%	0
2026-10-27	24K	66K	36.5%	0
2026-10-26	39K	79K	49.1%	0
2026-10-23	30K	59K	50.5%	0
2026-10-22	26K	65K	39.5%	0
2026-10-21	24K	61K	39.2%	0
2026-10-20	39K	116K	33.2%	0
2026-10-19	27K	97K	28.0%	0
2026-10-16	24K	45K	53.1%	0
2026-10-15	22K	37K	60.4%	0
2026-10-14	41K	62K	66.5%	0
2026-10-13	14K	56K	25.5%	40
2026-10-12	13K	24K	54.3%	0
2026-10-09	45K	69K	64.5%	2
2026-10-08	41K	76K	53.4%	253
2026-10-07	17K	29K	57.1%	0
2026-10-06	65K	121K	53.4%	0
2026-10-05	61K	122K	50.2%	200
2026-10-02	91K	227K	40.1%	10
2026-10-01	36K	158K	22.6%	0
2026-09-30	46K	83K	55.1%	0
2026-09-29	18K	74K	24.8%	0
2026-09-28	31K	78K	39.7%	0
2026-09-25	23K	90K	26.0%	0
2026-09-24	29K	145K	19.8%	796
2026-09-23	66K	193K	34.4%	0
2026-09-22	28K	134K	20.8%	0

Fails to deliver

SEC, the last 30 settlement dates with a fail. JSON

As of 18 September 2026, the fails-to-deliver balance in RNA is 706 shares, down 490 shares over the last settlement date. Over the last 30 readings it ranged from 1 share (13 April 2026) to 85,774 shares (6 March 2026). The latest reading sits at the bottom of that range.

Settlement	Shares failed	Price	Value
2026-09-18	706	$9.56	$7K
2026-09-15	1,196	$10.21	$12K
2026-09-10	48	$10.51	$504
2026-09-08	749	$14.19	$11K
2026-09-04	603	$14.60	$9K
2026-09-03	651	$14.06	$9K
2026-08-21	3,946	$13.48	$53K
2026-08-17	183	$12.84	$2K
2026-08-07	488	$12.11	$6K
2026-07-30	304	$11.18	$3K
2026-07-27	5,055	$11.49	$58K
2026-07-09	62	$13.37	$829
2026-07-06	82	$13.65	$1K
2026-06-26	5,617	$12.78	$72K
2026-06-12	2,182	$12.43	$27K
2026-06-11	4	$11.67	$47
2026-05-20	67	$12.95	$868
2026-05-13	2,452	$13.14	$32K
2026-05-11	1	$13.07	$13
2026-05-05	3	$12.87	$39
2026-04-16	14	$14.54	$204
2026-04-13	1	$12.71	$13
2026-04-07	2,034	$13.67	$28K
2026-04-01	233	$13.37	$3K
2026-03-31	8	$13.55	$108
2026-03-26	15	$13.09	$196
2026-03-17	1,204	$13.79	$17K
2026-03-11	30	$14.67	$440
2026-03-06	85,774	$15.47	$1.3M
2026-03-05	1,094	$16.54	$18K

Insider trades

SEC Form 4, newest first. JSON

No open-market insider trades were reported for RNA in the last 90 days. The most recent filings are listed below. Latest filing: Hoyos Rocio Martin (Chief Strategy Officer) on 2026-09-18.

Date	Insider	Title	Type	Shares	Price	Value	Owned after
2026-09-18	Hoyos Rocio Martin	Chief Strategy Officer	Tax withholding	8K	$8.95	$74K	38K
2026-09-18	Winslow Brendan R.	Chief Financial Officer	Tax withholding	7K	$8.95	$60K	37K
2026-09-18	Gallagher Kathleen P.	See Remarks	Tax withholding	12K	$8.95	$104K	120K
2026-09-18	Kenney Stephanie	See Remarks	Tax withholding	2K	$8.95	$21K	33K
2026-09-18	Boyce Sarah	Director	Tax withholding	126K	$8.95	$1.1M	139K
2026-09-18	Flanagan W. Michael	Director	Tax withholding	23K	$8.95	$204K	32K
2026-09-18	Hughes Steven George	Chief Medical Officer	Tax withholding	21K	$8.95	$192K	52K
2026-09-18	Younis Husam	Chief Scientific Officer	Tax withholding	11K	$8.95	$100K	41K
2026-04-20	Kenney Stephanie	See Remarks	Grant	30K	$0.00	$0	35K
2026-04-20	Hughes Steven George	Chief Medical Officer	Grant	30K	$0.00	$0	73K
2026-04-20	Winslow Brendan R.	Chief Financial Officer	Grant	30K	$0.00	$0	44K
2026-04-20	Gallagher Kathleen P.	See Remarks	Grant	103K	$0.00	$0	131K
2026-04-20	Hoyos Rocio Martin	Chief Strategy Officer	Grant	30K	$0.00	$0	47K
2026-04-20	Younis Husam	Chief Scientific Officer	Grant	30K	$0.00	$0	53K

Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.

Large holders (13D and 13G)

One row per reporting person with its latest filing, newest first. JSON

4 holders report 5% or more of RNA in their latest filing, all on Schedule 13G (passive). The largest reported stake is Sessa Capital IM, L.P. at 8.8% of the class (1,500,000 shares), filed 2026-08-14 for an event on 2026-06-30.

Filed	Form	Holder	Shares	Of class	Event
2026-08-14	13G/Ano. 1	RA Capital Management, L.P.investment adviser, partnership	0	0.0%	2026-06-30
2026-08-14	13G/Ano. 1	Peter Kolchinskyparent holding company, individual	0	0.0%	2026-06-30
2026-08-14	13G/Ano. 1	Rajeev Shahparent holding company, individual	0	0.0%	2026-06-30
2026-08-14	13G/Ano. 1	RA Capital Healthcare Fund, L.P.partnership	0	0.0%	2026-06-30
2026-08-14	13G	Sessa Capital IM, L.P.investment adviser, partnership	1.5M	8.8%	2026-06-30
2026-08-14	13G	John Petryparent holding company, individual	1.5M	8.8%	2026-06-30
2026-08-14	13G/Ano. 1	T. Rowe Price Associates, Inc.investment adviser	1.5M	8.6%	2026-06-30
2026-07-27	13G/Ano. 1	BlackRock, Inc.parent holding company	1.1M	6.6%	2026-06-30

13F holders

Tracked managers holding RNA at their latest 13F. JSON

5 of the 30 tracked managers held RNA at their latest 13F, $10.8M in total at quarter-end prices. Two Sigma Investments is the largest at $4.6M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 4 added shares and 1 cut.

Fund	Quarter	Shares	Value	Of portfolio	Change in shares
Two Sigma Investments	2026-06-30	345K	$4.6M	0.00%	+167K
Millennium Management	2026-06-30	201K	$2.7M	0.00%	+10K
AQR Capital Management	2026-06-30	172K	$2.3M	0.00%	new
Citadel Advisors	2026-06-30	68K	$910K	0.00%	-42K
Renaissance Technologies	2026-06-30	15K	$201K	0.00%	new

Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.

What this page is

Atrium Therapeutics in the regulatory record

Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.

Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.

This page follows Atrium Therapeutics (RNA), SEC CIK 2093101, listed on Nasdaq, classified by the SEC as pharmaceutical preparations. The cross-market tables live on the short interest and insider transactions hubs.

Source and updates

Short interest: FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
Daily short volume: FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-02.JSON and CSV
Fails to deliver: SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-09-18.JSON and CSV
Large holders: SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-08-14.JSON and CSV
13F holders: SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
Earnings dates: SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-08-13.JSON and CSV
Insider trades: SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-09-18.JSON and CSV
Company record: EDGAR filing index for CIK 2093101Ticker, name and exchange from the SEC's company list, refreshed weekly.
Rate limits: 10 requests a minute without a key, 30 with a free key from a free account.

How to read it

Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.

Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.

Other companies the SEC classifies as pharmaceutical preparations

Other company pages

Datasets

Frequently Asked Questions

How much of RNA is sold short?

3,726,302 shares were held short at the 2026-10-15 settlement, 12.9 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.

What is RNA's daily short volume?

On 2026-11-02, 74,885 of the 120,657 RNA shares reported to FINRA were sold short, 62.1% of the day's reported volume. Short volume is a flow for one day, not a position.

Does RNA have fails to deliver?

The SEC's latest file shows 706 RNA shares failed to deliver at settlement 2026-09-18. Fails are reported per settlement date and published twice a month with a lag.

Are RNA insiders buying or selling?

No open-market insider trades were reported for RNA in the last 90 days. The most recent filings are listed below. Latest filing: Hoyos Rocio Martin (Chief Strategy Officer) on 2026-09-18.

Who owns 5% or more of RNA?

Which tracked 13F managers own RNA?

5 of the 30 tracked 13F managers held RNA shares at their latest filing, $10.8M in all. The largest: Two Sigma Investments (345K shares, $4.6M), Izzy Englander's Millennium Management (201K shares, $2.7M), Cliff Asness's AQR Capital Management (172K shares, $2.3M), Ken Griffin's Citadel Advisors (68K shares, $910K), Renaissance Technologies (15K shares, $201K).

Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.