There is a long list of 314 institutional holders of IMGN within the last two holding periods in our database of 13F filers, so we've sorted through to present to you just the top 50 institutional holders of IMGN by largest to smallest position reported in the institutional investor's latest 13F filing. In the institutional-holders-of-IMGN table below, the initial column indicates the name of each top institutional holder of IMGN, with a link to that fund's top holdings. The next columns indicate the amount of IMGN stock held by each of the institutional holders of IMGN, followed by the IMGN position size held by the institution, and finally the date of the quarterly 13F filing period the holdings data represents for that institution.

Holder	Amount	Position Size ($ in 1000's)	As of
Vanguard Group Inc.	25,466,950	$755,095	12/31/2023
IMGN	25,466,950	$755,095	12/31/2023
RA Capital Management L.P.	23,750,601	$704,205	12/31/2023
IMGN	23,750,601	$704,205	12/31/2023
BlackRock Inc.	21,824,392	$647,093	12/31/2023
IMGN	21,824,392	$647,093	12/31/2023
Redmile Group LLC	16,423,922	$486,969	12/31/2023
IMGN	16,423,922	$486,969	12/31/2023
Janus Henderson Group PLC	11,043,986	$327,489	12/31/2023
IMGN	11,043,986	$327,489	12/31/2023
State Street Corp	8,075,671	$239,444	12/31/2023
IMGN	8,075,671	$239,444	12/31/2023
Fairmount Funds Management LLC	5,929,592	$175,812	12/31/2023
IMGN	5,929,592	$175,812	12/31/2023
Norges Bank	5,539,334	$164,241	12/31/2023
IMGN	5,539,334	$164,241	12/31/2023
Geode Capital Management LLC	5,382,875	$159,620	12/31/2023
IMGN	5,382,875	$159,620	12/31/2023
FIL Ltd	5,360,000	$158,924	12/31/2023
IMGN	5,360,000	$158,924	12/31/2023
Pentwater Capital Management LP		$138,243	12/31/2023
IMGN	5,662,500	$167,893	12/31/2023
Put	1,000,000	$29,650	12/31/2023
Millennium Management LLC		$134,744	12/31/2023
IMGN	4,473,868	$132,650	12/31/2023
Call	78,300	$2,322	12/31/2023
Put	7,700	$228	12/31/2023
D. E. Shaw & Co. Inc.	4,522,797	$134,101	12/31/2023
IMGN	4,522,797	$134,101	12/31/2023
Morgan Stanley	4,109,177	$121,837	12/31/2023
IMGN	4,109,177	$121,837	12/31/2023
Balyasny Asset Management LLC		$98,576	12/31/2023
Call	1,827,900	$54,197	12/31/2023
IMGN	1,496,758	$44,379	12/31/2023
Voloridge Investment Management LLC	3,221,231	$95,509	12/31/2023
IMGN	3,221,231	$95,509	12/31/2023
Boxer Capital LLC	2,961,000	$87,794	12/31/2023
IMGN	2,961,000	$87,794	12/31/2023
Maverick Capital Ltd.	2,493,217	$73,924	12/31/2023
IMGN	2,493,217	$73,924	12/31/2023
Northern Trust Corp	2,328,671	$69,045	12/31/2023
IMGN	2,328,671	$69,045	12/31/2023
TIG Advisors LLC	2,313,670	$68,600	12/31/2023
IMGN	2,313,670	$68,600	12/31/2023
Tang Capital Management LLC	2,199,137	$65,204	12/31/2023
IMGN	2,199,137	$65,204	12/31/2023
JPMorgan Chase & Co.		$61,045	12/31/2023
IMGN	2,063,254	$61,175	12/31/2023
Put	4,400	$130	12/31/2023
Nuveen Asset Management LLC	2,052,894	$60,868	12/31/2023
IMGN	2,052,894	$60,868	12/31/2023
Omni Event Management Ltd	2,036,155	$60,372	12/31/2023
IMGN	2,036,155	$60,372	12/31/2023
Wellington Management Group LLP	1,954,413	$57,948	12/31/2023
IMGN	1,954,413	$57,948	12/31/2023
Charles Schwab Investment Management Inc.	1,892,446	$56,111	12/31/2023
IMGN	1,892,446	$56,111	12/31/2023
Avidity Partners Management LP	1,829,215	$54,236	12/31/2023
IMGN	1,829,215	$54,236	12/31/2023
Healthcare of Ontario Pension Plan Trust Fund	1,785,296	$52,934	12/31/2023
IMGN	1,785,296	$52,934	12/31/2023
Alpine Associates Management Inc.	1,761,300	$52,223	12/31/2023
IMGN	1,761,300	$52,223	12/31/2023
Emerald Advisers LLC	1,744,981	$51,739	12/31/2023
IMGN	1,744,981	$51,739	12/31/2023
Renaissance Technologies LLC	1,631,240	$48,366	12/31/2023
IMGN	1,631,240	$48,366	12/31/2023
Magnetar Financial LLC	1,629,285	$48,308	12/31/2023
IMGN	1,629,285	$48,308	12/31/2023
Sofinnova Investments Inc.	1,546,902	$45,866	12/31/2023
IMGN	1,546,902	$45,866	12/31/2023
Alliancebernstein L.P.	1,507,809	$44,707	12/31/2023
IMGN	1,507,809	$44,707	12/31/2023
CNH Partners LLC	1,429,078	$42,372	12/31/2023
IMGN	1,429,078	$42,372	12/31/2023
Kynam Capital Management LP	1,422,503	$42,177	12/31/2023
IMGN	1,422,503	$42,177	12/31/2023
Affinity Asset Advisors LLC	1,404,608	$41,647	12/31/2023
IMGN	1,404,608	$41,647	12/31/2023
QVT Financial LP	1,375,900	$40,795	12/31/2023
IMGN	1,375,900	$40,795	12/31/2023
Westchester Capital Management LLC	1,364,927	$40,470	12/31/2023
IMGN	1,364,927	$40,470	12/31/2023
Group One Trading L.P.		$35,488	12/31/2023
Call	1,475,200	$43,740	12/31/2023
Put	278,300	$8,252	12/31/2023
Goldman Sachs Group Inc.	1,189,485	$35,268	12/31/2023
IMGN	1,189,485	$35,268	12/31/2023
Emerald Mutual Fund Advisers Trust	1,188,209	$35,230	12/31/2023
IMGN	1,188,209	$35,230	12/31/2023
Marshall Wace LLP	1,187,027	$35,195	12/31/2023
IMGN	1,187,027	$35,195	12/31/2023
Artisan Partners Limited Partnership	1,172,323	$34,759	12/31/2023
IMGN	1,172,323	$34,759	12/31/2023
Principal Financial Group Inc.	1,127,402	$33,427	12/31/2023
IMGN	1,127,402	$33,427	12/31/2023
Candriam Luxembourg S.C.A.	1,122,598	$33,287	12/31/2023
IMGN	1,122,598	$33,287	12/31/2023
Price T Rowe Associates Inc. MD	1,088,213	$32,267	12/31/2023
IMGN	1,088,213	$32,267	12/31/2023
Deutsche Bank AG	1,065,880	$31,603	12/31/2023
IMGN	1,065,880	$31,603	12/31/2023
Bank of New York Mellon Corp	1,063,500	$31,533	12/31/2023
IMGN	1,063,500	$31,533	12/31/2023
Jane Street Group LLC		$30,526	12/31/2023
Call	742,100	$22,003	12/31/2023
IMGN	634,353	$18,809	12/31/2023
Put	346,900	$10,286	12/31/2023