There is a long list of 174 institutional holders of AMBC 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 AMBC by largest to smallest position reported in the institutional investor's latest 13F filing. In the institutional-holders-of-AMBC table below, the initial column indicates the name of each top institutional holder of AMBC, with a link to that fund's top holdings. The next columns indicate the amount of AMBC stock held by each of the institutional holders of AMBC, followed by the AMBC 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
BlackRock Inc.	7,285,404	$120,063	12/31/2023
AMBC	7,285,404	$120,063	12/31/2023
Vanguard Group Inc.	4,835,365	$79,687	12/31/2023
AMBC	4,835,365	$79,687	12/31/2023
Dimensional Fund Advisors LP	2,603,679	$42,908	12/31/2023
AMBC	2,603,679	$42,908	12/31/2023
FMR LLC	2,075,509	$34,204	12/31/2023
AMBC	2,075,509	$34,204	12/31/2023
Repertoire Partners LP		$30,194	12/31/2023
Call	1,266,900	$20,879	12/31/2023
AMBC	565,233	$9,315	12/31/2023
State Street Corp	1,626,127	$26,799	12/31/2023
AMBC	1,626,127	$26,799	12/31/2023
Invesco Ltd.	1,032,814	$17,021	12/31/2023
AMBC	1,032,814	$17,021	12/31/2023
Geode Capital Management LLC	946,179	$15,595	12/31/2023
AMBC	946,179	$15,595	12/31/2023
Boussard & Gavaudan Investment Management LLP	853,531	$13,887	12/31/2023
AMBC	853,531	$13,887	12/31/2023
Bracebridge Capital LLC	799,234	$13,171	12/31/2023
AMBC	799,234	$13,171	12/31/2023
Nuveen Asset Management LLC	756,478	$12,467	12/31/2023
AMBC	756,478	$12,467	12/31/2023
Deutsche Bank AG	740,430	$12,202	12/31/2023
AMBC	740,430	$12,202	12/31/2023
Prudential Financial Inc.	730,120	$12,032	12/31/2023
AMBC	730,120	$12,032	12/31/2023
Susquehanna International Group LLP		$11,314	12/31/2023
Call	456,100	$7,517	12/31/2023
AMBC	280,112	$4,616	12/31/2023
Put	49,700	$819	12/31/2023
Goldman Sachs Group Inc.	649,686	$10,707	12/31/2023
AMBC	649,686	$10,707	12/31/2023
Charles Schwab Investment Management Inc.	649,577	$10,705	12/31/2023
AMBC	649,577	$10,705	12/31/2023
Simplex Trading LLC		$9,492	03/31/2024
Call	340,600	$5,323	03/31/2024
AMBC	279,725	$4,372	03/31/2024
Put	13,000	$203	03/31/2024
Morgan Stanley	551,190	$9,084	12/31/2023
AMBC	551,190	$9,084	12/31/2023
American Century Companies Inc.	519,702	$8,565	12/31/2023
AMBC	519,702	$8,565	12/31/2023
Northern Trust Corp	504,697	$8,317	12/31/2023
AMBC	504,697	$8,317	12/31/2023
D. E. Shaw & Co. Inc.	491,719	$8,104	12/31/2023
AMBC	491,719	$8,104	12/31/2023
Citadel Advisors LLC		$7,541	12/31/2023
AMBC	404,310	$6,663	12/31/2023
Call	167,800	$2,765	12/31/2023
Put	114,500	$1,887	12/31/2023
Walleye Trading LLC		$7,104	12/31/2023
AMBC	471,975	$7,778	12/31/2023
Put	46,300	$763	12/31/2023
Call	5,400	$89	12/31/2023
Jupiter Asset Management Ltd.	426,663	$7,031	12/31/2023
AMBC	426,663	$7,031	12/31/2023
Bank of New York Mellon Corp	422,014	$6,596	03/31/2024
AMBC	422,014	$6,596	03/31/2024
Bridgeway Capital Management Inc.	390,922	$6,442	12/31/2023
AMBC	390,922	$6,442	12/31/2023
Hotchkis & Wiley Capital Management LLC	386,530	$6,370	12/31/2023
AMBC	386,530	$6,370	12/31/2023
AQR Capital Management LLC	367,839	$6,062	12/31/2023
AMBC	367,839	$6,062	12/31/2023
Hsbc Holdings PLC	301,777	$4,919	12/31/2023
AMBC	301,777	$4,919	12/31/2023
Jane Street Group LLC		$3,692	12/31/2023
AMBC	199,059	$3,280	12/31/2023
Call	25,000	$412	12/31/2023
Principal Financial Group Inc.	234,538	$3,666	03/31/2024
AMBC	234,538	$3,666	03/31/2024
UBS Group AG		$3,390	12/31/2023
Call	177,500	$2,925	12/31/2023
AMBC	28,204	$465	12/31/2023
Caption Management LLC		$3,381	12/31/2023
AMBC	125,210	$2,063	12/31/2023
Call	80,000	$1,318	12/31/2023
Gendell Jeffrey L	199,255	$3,284	12/31/2023
AMBC	199,255	$3,284	12/31/2023
Ameriprise Financial Inc.	189,336	$3,120	12/31/2023
AMBC	189,336	$3,120	12/31/2023
Renaissance Technologies LLC	186,744	$3,078	12/31/2023
AMBC	186,744	$3,078	12/31/2023
Harbor Advisors LLC	196,382	$3,069	03/31/2024
AMBC	196,382	$3,069	03/31/2024
Public Sector Pension Investment Board	165,792	$2,732	12/31/2023
AMBC	165,792	$2,732	12/31/2023
Voya Investment Management LLC	165,627	$2,730	12/31/2023
AMBC	165,627	$2,730	12/31/2023
Russell Investments Group Ltd.	157,407	$2,594	12/31/2023
AMBC	157,407	$2,594	12/31/2023
Empowered Funds LLC	141,627	$2,334	12/31/2023
AMBC	141,627	$2,334	12/31/2023
Rhumbline Advisers	135,245	$2,229	12/31/2023
AMBC	135,245	$2,229	12/31/2023
Wells Fargo & Company MN		$2,182	12/31/2023
AMBC	127,786	$2,106	12/31/2023
Call	4,600	$76	12/31/2023
Group One Trading L.P.		$2,166	12/31/2023
AMBC	86,430	$1,424	12/31/2023
Call	45,000	$742	12/31/2023
GTS Securities LLC	129,982	$2,142	12/31/2023
AMBC	129,982	$2,142	12/31/2023
Legal & General Group Plc	124,907	$2,058	12/31/2023
AMBC	124,907	$2,058	12/31/2023
First Trust Advisors LP	124,197	$2,047	12/31/2023
AMBC	124,197	$2,047	12/31/2023
Brandywine Global Investment Management LLC	122,146	$2,013	12/31/2023
AMBC	122,146	$2,013	12/31/2023
Gator Capital Management LLC	121,435	$2,001	12/31/2023
AMBC	121,435	$2,001	12/31/2023
Bank of America Corp DE	109,200	$1,800	12/31/2023
AMBC	109,200	$1,800	12/31/2023