Ticker · CUSIP 023139884

OSG

AMBAC FINL GROUP INC
Financial Services·Insurance - Specialty
···Share
Holders (tracked)
13
Combined shares
2,533,506
Combined value
$19.16M
Last close
—
Quarter
2025Q4
Tracked holders · last 8 quarters
+5 vs previous quarter over the last 8.
13102024Q12025Q4

SEC event timeline

18 events
  1. Ken Griffin (Citadel Advisors) added2026-02-17
    +115,740 shares · 2025Q4
    13F
  2. D.E. Shaw & Co. trimmed2026-02-17
    −74,599 shares · 2025Q4
    13F
  3. Two Sigma Investments opened position2026-02-17
    +45,044 shares · 2025Q4
    13F
  4. Izzy Englander (Millennium Mgmt) trimmed2026-02-17
    −397,613 shares · 2025Q4
    13F
  5. Steve Cohen (Point72) opened position2026-02-17
    +103,544 shares · 2025Q4
    13F
  6. Paul Tudor Jones (Tudor Investment) opened position2026-02-17
    +94,000 shares · 2025Q4
    13F
  7. AQR Capital Management trimmed2026-02-17
    −12,434 shares · 2025Q4
    13F
  8. Renaissance Technologies trimmed2026-02-12
    −64,042 shares · 2025Q4
    13F
  9. Norges Bank (Norway SWF) opened position2026-02-10
    +75,000 shares · 2025Q4
    13F
  10. Paul Tudor Jones (Tudor Investment) exited2025-12-09
    −305,702 shares · 2025Q3
    13F
  11. D.E. Shaw & Co. trimmed2025-11-14
    −216,922 shares · 2025Q3
    13F
  12. Izzy Englander (Millennium Mgmt) trimmed2025-11-14
    −295,146 shares · 2025Q3
    13F
  13. T. Rowe Price added2025-11-14
    +18,736 shares · 2025Q3
    13F
  14. AQR Capital Management added2025-11-14
    +31,262 shares · 2025Q3
    13F
  15. Two Sigma Investments exited2025-11-14
    −43,923 shares · 2025Q3
    13F
  16. Norges Bank (Norway SWF) exited2025-11-13
    −75,000 shares · 2025Q3
    13F
  17. Renaissance Technologies trimmed2025-11-13
    −96,900 shares · 2025Q3
    13F
  18. Norges Bank (Norway SWF) trimmed2025-11-12
    −78,400 shares · 2024Q3
    13F

Insider activity

No insider transactions in the last 30 days.
View full insider history for OSG →

Who moved on this name in 2025Q4

13F transactions reported for the latest quarter, grouped by direction.
New positions4
Added to1
Trimmed4
Exited0
—

Institutional ownership over time

Distinct super-investors holding this ticker · combined dollar value, by quarter.
QuarterHoldersCombined value
2022Q1
10
$1.39B
2022Q2
9
$82.9M
2022Q3
9
$96K
2022Q4
12
$142.0M
2023Q1
12
$128.5M
2023Q2
11
$116.7M
2023Q3
10
$98.6M
2023Q4
9
$139.9M
2024Q1
10
$127.9M
2024Q2
11
$118.7M
2024Q3
11
$32.3M
2024Q4
12
$26.5M
2025Q1
10
$26.2M
2025Q2
11
$23.9M
2025Q3
8
$19.1M
2025Q4
13
$19.2M

Who owns OSG

13 super-investors · 2025Q4
Tracked stake
2.53M
shares
Combined value
$19M
% of shares outstanding
—
shares-out unknown
Quarter action mix
New5Added3Trim4Held1
#ManagerSharesValue
1Ken Griffin
Citadel Advisors
1.33M$10M
2Izzy Englander
Millennium Mgmt
303.3K$2M
3Ken Griffin
Citadel Advisors
287.3K$2M
4Steve Cohen
Point72
103.5K$806K
5Ken Griffin
Citadel Advisors
87.0K$677K
6Norges Bank
Norway SWF
75.0K$584K
7AQR Capital Management70.1K$546K
8Paul Tudor Jones
Tudor Investment
48.5K$377K
9Paul Tudor Jones
Tudor Investment
45.5K$354K
10Two Sigma Investments45.0K$350K
11D.E. Shaw & Co.44.1K$343K
12Renaissance Technologies25.2K$196K
13T. Rowe Price70.9K$552

Recent moves

20 transactions
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