IRON · Disc Medicine, Inc. · Shareholders & Ownership

$79.48 +0.55 (+0.70%) At close · Oct 20

Russell 2000 member Rebalance outlook locked

Market Cap

$3.05B

38.39M

Volume · Oct 20 2.21M Avg daily vol (3M) 646.26K

Every disclosed holder of IRON in one list: 13F institutions, Schedule 13D and 13G filers, insiders (Forms 3, 4 and 5) and registered funds, each from its own latest filing. Holders nest by CIK and SEC reporting links, never by name, and each is summed once.

How the holder list picks a filing →

Who Owns IRON

13F quarter Sep 30, 2026, combined view: filers that have not filed yet carry their Jun 30, 2026 positions

No chart: the summed disclosures exceed shares outstanding, so they are not parts of one whole.

Holder group	Holders	Shares	% Out	Summed
Institutional (13F)	215	43,506,953	113.32%	Yes
Insiders (Forms 3, 4, 5)	9	4,836,349	12.60%	Yes
13D/G-only blocks	4	3,800,627	9.90%	Yes
Remaining	—	13,751,085	-35.82%	Negative
Registered funds (N-PORT, not summed)	224	15,188,086	39.56%	No

Shares outstanding: 38,392,844, the issuer's latest cover-page count restated onto today's split basis.

Remaining is negative: the summed disclosures exceed shares outstanding, as when filings are dated at different times or holders that do not disclose their links count the same shares. It is flagged, not clipped.

13D/G-only counts each filer's latest 13D or 13G that no 13F report of the listing contains, that names no 13F filer and that no counted insider files. Funds are never summed: their shares sit inside their advisers' 13F reports.

Holders of IRON

One row per holder Every filing By ultimate parent

All 13F Funds Insiders 13D/G Non-US

#	Holder	Shares	% Out	Change	As of	Notes
1	FMR LLC 13F CIK 315066 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	4,894,473	12.75%	-692,421	Jun 30, 2026	carried, not yet filed for the newest quarter
1.1	FMR LLC 13G CIK 315066 · Holding company · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	4,875,472	12.70%	-31,686	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
1.2	Strategic Advisers Fidelity U.S. Total Stock Fund Fund S000061481 · Registered fund · May 31, 2026 Fidelity Rutland Square Trust II, not summed	1,889,838	4.92%	+233,215	May 31, 2026	Fidelity Rutland Square Trust II, not summed
1.3	Select Biotechnology Portfolio Fund S000007486 · Registered fund · May 31, 2026 Fidelity Select Portfolios, not summed	454,774	1.18%	-77,400	May 31, 2026	Fidelity Select Portfolios, not summed
1.4	Select Health Care Portfolio Fund S000007466 · Registered fund · May 31, 2026 Fidelity Select Portfolios, not summed	450,000	1.17%	-200,000	May 31, 2026	Fidelity Select Portfolios, not summed
1.5	Fidelity Small Cap Index Fund Fund S000033638 · Registered fund · Jul 31, 2026 Fidelity Salem Street Trust, not summed	309,253	0.81%	+37,627	Jul 31, 2026	Fidelity Salem Street Trust, not summed
2	AI DMI LLC Insider CIK 1890993 · Oct 22, 2025 10% Owner, issuer-wide	2,814,379	7.33%	-744,047	Oct 22, 2025	10% Owner, issuer-wide
2.1	AI DMI LLC 13D CIK 1890993 · Unknown · Oct 20, 2025 not summed	3,018,460	7.86%	-744,047	Oct 20, 2025	not summed
3	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	2,467,899	6.43%	+194,068	Jun 30, 2026	carried, not yet filed for the newest quarter
3.1	iShares Russell 2000 ETF Fund S000004344 · Registered fund · Jun 30, 2026 iShares Trust, not summed	739,640	1.93%	+70,252	Jun 30, 2026	iShares Trust, not summed
3.2	iShares Russell 2000 Growth ETF Fund S000004343 · Registered fund · Jun 30, 2026 iShares Trust, not summed	261,158	0.68%	+36,715	Jun 30, 2026	iShares Trust, not summed
3.3	iShares Biotechnology ETF Fund S000004350 · Registered fund · Jun 30, 2026 iShares Trust, not summed	196,211	0.51%	-18,678	Jun 30, 2026	iShares Trust, not summed
3.4	Master Small Cap Index Series Fund S000002716 · Registered fund · Jun 30, 2026 Quantitative Master Series LLC, not summed	52,891	0.14%	+8,244	Jun 30, 2026	Quantitative Master Series LLC, not summed
3.5	iShares Core S&P Total U.S. Stock Market ETF Fund S000004317 · Registered fund · Jun 30, 2026 iShares Trust, not summed	49,099	0.13%	+8,972	Jun 30, 2026	iShares Trust, not summed
4	RA CAPITAL MANAGEMENT, L.P. 13F CIK 1346824 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,450,221	6.38%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
5	JPMORGAN CHASE & CO 13F CIK 19617 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	1,875,795	4.89%	+504,315	Jun 30, 2026	carried, not yet filed for the newest quarter
6	PRICE T ROWE ASSOCIATES INC /MD/ 13F CIK 80255 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,875,399	4.88%	+326,049	Jun 30, 2026	carried, not yet filed for the newest quarter
6.1	T. Rowe Price New Horizons Fund, Inc. Fund S000002106 · Registered fund · Jun 30, 2026 T. ROWE PRICE NEW HORIZONS FUND, INC., not summed	566,760	1.48%	+61,774	Jun 30, 2026	T. ROWE PRICE NEW HORIZONS FUND, INC., not summed
6.2	T. Rowe Price Integrated U.S. Small-Cap Growth Equity Fund Fund S000002074 · Registered fund · Jun 30, 2026 T. ROWE PRICE INTEGRATED EQUITY FUNDS, INC., not summed	375,603	0.98%	+58,100	Jun 30, 2026	T. ROWE PRICE INTEGRATED EQUITY FUNDS, INC., not summed
6.3	T. Rowe Price Health Sciences Fund, Inc. Fund S000002088 · Registered fund · Jun 30, 2026 T. ROWE PRICE HEALTH SCIENCES FUND, INC., not summed	132,359	0.34%	-54,246	Jun 30, 2026	T. ROWE PRICE HEALTH SCIENCES FUND, INC., not summed
6.4	T. Rowe Price Small-Mid Cap ETF Fund S000079837 · Registered fund · Jun 30, 2026 T. Rowe Price Exchange-Traded Funds, Inc., not summed	63,785	0.17%	+26,609	Jun 30, 2026	T. Rowe Price Exchange-Traded Funds, Inc., not summed
6.5	T. Rowe Price Integrated U.S. Small-Mid Cap Core Equity Fund Fund S000052904 · Registered fund · Jun 30, 2026 T. ROWE PRICE INTEGRATED EQUITY FUNDS, INC., not summed	43,222	0.11%	+13,181	Jun 30, 2026	T. ROWE PRICE INTEGRATED EQUITY FUNDS, INC., not summed
7	WELLINGTON MANAGEMENT GROUP LLP 13F CIK 902219 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	1,741,351	4.54%	+5,975	Jun 30, 2026	carried, not yet filed for the newest quarter
8	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	1,648,836	4.29%	-49,408	Jun 30, 2026	carried, not yet filed for the newest quarter
8.1	State Street(R) SPDR(R) S&P(R) Biotech ETF Fund S000010018 · Registered fund · Jun 30, 2026 SPDR SERIES TRUST, not summed	958,601	2.50%	-53,447	Jun 30, 2026	SPDR SERIES TRUST, not summed
8.2	STATE STREET SMALL/MID CAP EQUITY INDEX PORTFOLIO Fund S000050332 · Registered fund · Jun 30, 2026 STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed	9,800	0.03%	+200	Jun 30, 2026	STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed
8.3	State Street Total Return V.I.S. Fund Fund S000001637 · Registered fund · Jun 30, 2026 STATE STREET VARIABLE INSURANCE SERIES FUNDS INC, not summed	714	0.00%	+61	Jun 30, 2026	STATE STREET VARIABLE INSURANCE SERIES FUNDS INC, not summed
8.4	State Street Balanced Index Fund Fund S000082802 · Registered fund · Jun 30, 2026 STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed	123	0.00%	0	Jun 30, 2026	STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed
9	Vestal Point Capital, LP 13F CIK 1974915 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,550,000	4.04%	+850,000	Jun 30, 2026	carried, not yet filed for the newest quarter
10	Atlas Venture Life Science Advisors, LLC 13F CIK 1917529 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,513,875	3.94%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
11	Ashiya Mona Insider CIK 1794070 · Mar 24, 2025 Director, issuer-wide	1,415,020	3.69%	-5,738	Mar 24, 2025	Director, issuer-wide
12	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,369,027	3.57%	-6,403	Jun 30, 2026	carried, not yet filed for the newest quarter
13	Frazier Life Sciences Management, L.P. 13F CIK 1892134 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,354,852	3.53%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
14	TCG Crossover Management, LLC 13F CIK 1839948 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,341,862	3.50%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
15	Paradigm Biocapital Advisors LP 13G CIK 1855655 · Registered investment adviser · Mar 31, 2025 Rule 13d-1(c), passive investor	1,210,971	3.15%	-286,749	Mar 31, 2025	Rule 13d-1(c), passive investor
16	BVF INC/IL 13F CIK 1056807 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,153,612	3.00%	-118,700	Jun 30, 2026	carried, not yet filed for the newest quarter
17	Assenagon Asset Management S.A. 13F CIK 1546007 · Unknown · Sep 30, 2026	1,119,458	2.92%	+735,300	Sep 30, 2026
18	James N. Topper 13G CIK 1863769 · Unknown · Jun 30, 2025 Rule 13d-1(c), passive investor	1,026,489	2.67%	-728,345	Jun 30, 2025	Rule 13d-1(c), passive investor
19	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	970,661	2.53%	-18,308	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
20	Woodline Partners LP 13F CIK 1784547 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	958,281	2.50%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
21	Siren, L.L.C. 13F CIK 2005245 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	888,401	2.31%	-100,000	Jun 30, 2026	carried, not yet filed for the newest quarter
22	Logos Global Management LP 13F CIK 1792126 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	875,000	2.28%	+315,000	Jun 30, 2026	carried, not yet filed for the newest quarter
23	Opaleye Management Inc. 13F CIK 1595855 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	855,000	2.23%	+434,000	Jun 30, 2026	carried, not yet filed for the newest quarter
24	Atlas Venture Fund X, L.P. 13D CIK 1628098 · Unknown · Dec 12, 2025	813,167	2.12%	-271,360	Dec 12, 2025
25	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	789,724	2.06%	+45,502	Jun 30, 2026	carried, not yet filed for the newest quarter
26	ADAGE CAPITAL PARTNERS GP, L.L.C. 13G CIK 1165408 · Registered investment adviser · Dec 31, 2023 Rule 13d-1(c), passive investor	750,000	1.95%	—	Dec 31, 2023	Rule 13d-1(c), passive investor
27	DEERFIELD MANAGEMENT COMPANY, L.P. 13F CIK 1009258 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	657,000	1.71%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
28	JPMorgan Mid Cap Growth Fund Fund S000003654 · Registered fund · Jun 30, 2026 JPMorgan Trust II, not summed	647,794	1.69%	+262,085	Jun 30, 2026	JPMorgan Trust II, not summed
29	DIMENSIONAL FUND ADVISORS LP 13F CIK 354204 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	569,018	1.48%	+174,571	Jun 30, 2026	carried, not yet filed for the newest quarter
29.1	U.S. SMALL CAP PORTFOLIO Fund S000000971 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	121,648	0.32%	+51,923	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
29.2	Dimensional U.S. Small Cap ETF Fund S000070906 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	119,817	0.31%	+7,628	Jul 31, 2026	Dimensional ETF Trust, not summed
29.3	U.S. MICRO CAP PORTFOLIO Fund S000000948 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	96,964	0.25%	+18,734	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
29.4	Dimensional U.S. Core Equity 2 ETF Fund S000070903 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	83,295	0.22%	+23,051	Jul 31, 2026	Dimensional ETF Trust, not summed
29.5	U.S. CORE EQUITY 2 PORTFOLIO Fund S000000980 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	28,751	0.07%	0	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
30	Bellevue Group AG 13F CIK 1674546 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	560,000	1.46%	+100,686	Jun 30, 2026	carried, not yet filed for the newest quarter
31	Saturn V Capital Management LP 13F CIK 1964437 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	524,730	1.37%	+74,804	Jun 30, 2026	carried, not yet filed for the newest quarter
32	ARMISTICE CAPITAL, LLC 13F CIK 1601086 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	460,000	1.20%	-76,000	Jun 30, 2026	carried, not yet filed for the newest quarter
33	JENNISON ASSOCIATES LLC 13F CIK 53417 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	439,520	1.14%	-170,862	Jun 30, 2026	carried, not yet filed for the newest quarter
34	Aberdeen Group plc 13F CIK 1716774 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	438,174	1.14%	+62,560	Jun 30, 2026	carried, not yet filed for the newest quarter
35	Palo Alto Investors LP 13F CIK 1306923 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	416,646	1.09%	+14,927	Jun 30, 2026	carried, not yet filed for the newest quarter
36	EVENTIDE ASSET MANAGEMENT, LLC 13F CIK 1442891 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	395,651	1.03%	+79	Jun 30, 2026	carried, not yet filed for the newest quarter
36.1	Eventide Healthcare & Life Sciences Fund Fund S000039514 · Registered fund · Jun 30, 2026 MUTUAL FUND SERIES TRUST, not summed	395,235	1.03%	0	Jun 30, 2026	MUTUAL FUND SERIES TRUST, not summed
36.2	Eventide Small Cap ETF Fund S000095403 · Registered fund · Jul 31, 2026 Strategy Shares, not summed	511	0.00%	+155	Jul 31, 2026	Strategy Shares, not summed
37	Pictet Asset Management Holding SA 13F CIK 1993888 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	385,375	1.00%	-1,630	Jun 30, 2026	carried, not yet filed for the newest quarter
38	LOOMIS SAYLES & CO L P 13F CIK 312348 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	381,864	0.99%	+64,642	Jun 30, 2026	carried, not yet filed for the newest quarter
38.1	Loomis Sayles Small Cap Growth Fund Fund S000006705 · Registered fund · Jun 30, 2026 LOOMIS SAYLES FUNDS II, not summed	206,644	0.54%	+29,159	Jun 30, 2026	LOOMIS SAYLES FUNDS II, not summed
39	Foresite Capital Management V, LLC 13F CIK 1792206 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	374,069	0.97%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
40	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	366,949	0.96%	+12,583	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
41	ORBIMED ADVISORS LLC 13F CIK 1055951 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	357,535	0.93%	-710,015	Jun 30, 2026	carried, not yet filed for the newest quarter
41.1	ORBIMED ADVISORS LLC Insider CIK 1055951 · Mar 24, 2025 10% Owner, issuer-wide, not summed	1,415,020	3.69%	-5,738	Mar 24, 2025	10% Owner, issuer-wide, not summed
42	BAKER BROS. ADVISORS LP 13F CIK 1263508 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	349,657	0.91%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
43	VANGUARD PORTFOLIO MANAGEMENT LLC 13F CIK 2100121 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	281,937	0.73%	+34,599	Jun 30, 2026	carried, not yet filed for the newest quarter
44	JPMorgan Small Cap Growth Fund Fund S000003859 · Registered fund · Jun 30, 2026 JPMorgan Trust II, not summed	274,234	0.71%	-14,411	Jun 30, 2026	JPMorgan Trust II, not summed
45	Octagon Capital Advisors LP 13F CIK 1839435 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	270,000	0.70%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
46	NORTHERN TRUST CORP 13F CIK 73124 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	264,990	0.69%	+17,795	Jun 30, 2026	carried, not yet filed for the newest quarter
46.1	Small Cap Index Fund Fund S000001245 · Registered fund · Jun 30, 2026 Northern Funds, not summed	14,276	0.04%	+1,354	Jun 30, 2026	Northern Funds, not summed
46.2	Small Cap Core Fund Fund S000001244 · Registered fund · Jun 30, 2026 Northern Funds, not summed	1,453	0.00%	-69	Jun 30, 2026	Northern Funds, not summed
46.3	FlexShares Morningstar US Market Factor Tilt Index Fund Fund S000033312 · Registered fund · Jul 31, 2026 FlexShares Trust, not summed	334	0.00%	+16	Jul 31, 2026	FlexShares Trust, not summed
47	Quisel John D Insider CIK 1586788 · Sep 15, 2026 Director, issuer-wide	262,064	0.68%	+36,000	Sep 15, 2026	Director, issuer-wide
48	CHARLES SCHWAB INVESTMENT MANAGEMENT INC 13F CIK 884546 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	257,382	0.67%	+6,187	Jun 30, 2026	carried, not yet filed for the newest quarter
48.1	Schwab U.S. Small-Cap ETF Fund S000026636 · Registered fund · May 31, 2026 SCHWAB STRATEGIC TRUST, not summed	152,195	0.40%	-2,651	May 31, 2026	SCHWAB STRATEGIC TRUST, not summed
48.2	Schwab Small-Cap Index Fund Fund S000005912 · Registered fund · Jul 31, 2026 SCHWAB CAPITAL TRUST, not summed	68,584	0.18%	+8,230	Jul 31, 2026	SCHWAB CAPITAL TRUST, not summed
48.3	Schwab Total Stock Market Index Fund Fund S000005913 · Registered fund · Jul 31, 2026 SCHWAB CAPITAL TRUST, not summed	19,425	0.05%	0	Jul 31, 2026	SCHWAB CAPITAL TRUST, not summed
48.4	Schwab U.S. Broad Market ETF Fund S000026631 · Registered fund · May 31, 2026 SCHWAB STRATEGIC TRUST, not summed	18,441	0.05%	0	May 31, 2026	SCHWAB STRATEGIC TRUST, not summed
49	Checkpoint Capital L.P. 13F CIK 1977548 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	240,125	0.63%	-46,536	Jun 30, 2026	carried, not yet filed for the newest quarter
50	VANGUARD FIDUCIARY TRUST CO 13F CIK 933478 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	225,198	0.59%	+7,762	Jun 30, 2026	carried, not yet filed for the newest quarter

57 more nested rows are not shown here; Every filing lists them all.

Shares are restated onto today's split basis. Change compares each row with the same holder's previous filing in the same source; a dash means there is none to compare. Nested 13D/G, insider and fund rows are not summed, since a 13F report already holds them.

Showing 1–50 of 323 holders

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Key facts CIK 1816736 CUSIP 254604101 13F (30d) 12 filings 12 filers Visit website Investor relations