AMBAC FINANCIAL GROUP INC (AMBC) Stock Institutional Trading Activity


AMBAC FINANCIAL GROUP INC (AMBC) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Third Avenue Management, Renaissance Technologies LLC, TCI Fund Management, and Arbiter Partners Capital Management. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q4 2017Renaissance Technologies LLCSell-94,800283,100$4,524
Q3 2017Renaissance Technologies LLCSell-125,000377,900$6,523
Q2 2017Renaissance Technologies LLCBuy261,700502,900$8,725
Q1 2017Renaissance Technologies LLCBuy80,400241,200$4,549
Q4 2016Renaissance Technologies LLCBuy10,000160,800$3,618
Q3 2016Renaissance Technologies LLCBuy85,566150,800$2,773
Q2 2016Renaissance Technologies LLCSell-36,16665,234$1,074
Q1 2016Renaissance Technologies LLCSell-73,100101,400$1,602
Q3 2015Renaissance Technologies LLCSell-55,700174,500$2,525
Q2 2015Renaissance Technologies LLCBuy3,100230,200$3,831
Q2 2015TCI Fund ManagementBuy1,985,7851,985,785$33,043
Q1 2015Renaissance Technologies LLCSell-284,400227,100$5,496
Q4 2014Renaissance Technologies LLCSell-76,900511,500$12,532
Q3 2014Renaissance Technologies LLCSell-15,500588,400$13,004
Q2 2014Arbiter Partners Capital ManagementSell-260,730292,327$7,983
Q2 2014Renaissance Technologies LLCBuy170,100603,900$16,493
Q1 2014Arbiter Partners Capital ManagementSell-212,141553,057$17,161
Q1 2014Renaissance Technologies LLCBuy433,800433,800$13,461
Q4 2013Arbiter Partners Capital ManagementSell-796,2985,000$123
Q4 2013Arbiter Partners Capital ManagementBuy760,198765,198$18,793
Q3 2013Arbiter Partners Capital ManagementBuy193,000801,298$14,536
Q2 2013Arbiter Partners Capital ManagementBuy608,298608,298$14,496

Frequently asked questions about AMBC activity

  • Which institutional owners are buying AMBC?

    Institutional owners buying AMBC include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in AMBC activity?

    "Buy" means an investor increased their reported position in AMBC compared to the prior reporting period. This reflects growing exposure to AMBAC FINANCIAL GROUP INC (AMBC) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in AMBC increasing?

    Institutional interest in AMBC can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.