Dimensional Fund Advisors LP filed an amended Schedule 13G reporting beneficial ownership of 2,141,047 shares of Ambac Financial Group Inc common stock, representing 4.6% of the class as of 09/30/2025. Dimensional reports sole voting power over 2,094,221 shares and sole dispositive power over 2,141,047 shares, while stating that all reported shares are owned by client Funds and that Dimensional disclaims beneficial ownership. The filing indicates these holdings are managed in the ordinary course of business and were not acquired to influence control.
Positive
Meaningful institutional stake:4.6% ownership (2,141,047 shares) signals material investor interest
Significant voting control: Sole voting power over 2,094,221 shares gives the adviser decisive voting authority on governance matters
Negative
Beneficial ownership disclaimed: Reported shares are owned by client Funds, introducing uncertainty about which underlying funds hold >5% exposure
No indication of intent to influence control: Certification states holdings are passive, so investors should not infer activist intent
Insights
Large passive stake: 4.6% ownership with substantial voting control.
The filing shows an 4.6% economic interest in Ambac through funds managed by Dimensional, with 2,094,221 shares under sole voting power. This signals a meaningful institutional position without an intent to influence control, per the certification.
Key dependencies include the composition of the underlying Funds and any reallocations; monitor quarterly holdings disclosures and fund-level flows over the next reporting cycle in Q4 2025 for material changes.
Disclosure emphasizes advisory role and a formal disclaimer of beneficial ownership.
The statement clarifies that the securities are owned by client Funds and that Dimensional acts as adviser or sub-adviser, which is standard for investment advisers reporting under Schedule 13G. The disclaimer limits attribution of direct beneficial ownership beyond regulatory reporting.
Watch for any future amendments or Schedule 13D filings that would indicate a change from passive to active intent, particularly within 45 days of any material shift in strategy or position size.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 1)
Ambac Financial Group Inc
(Name of Issuer)
Common Stock
(Title of Class of Securities)
023139884
(CUSIP Number)
09/30/2025
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
SCHEDULE 13G
CUSIP No.
023139884
1
Names of Reporting Persons
Dimensional Fund Advisors LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
2,094,221.00
6
Shared Voting Power
0.00
7
Sole Dispositive Power
2,141,047.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,141,047.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
4.6 %
12
Type of Reporting Person (See Instructions)
IA
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Ambac Financial Group Inc
(b)
Address of issuer's principal executive offices:
One World Trade Center, 41st Floor, New York, NY 10007
Item 2.
(a)
Name of person filing:
Dimensional Fund Advisors LP
(b)
Address or principal business office or, if none, residence:
6300 Bee Cave Road, Building One, Austin, TX 78746
(c)
Citizenship:
Delaware Limited Partnership
(d)
Title of class of securities:
Common Stock
(e)
CUSIP No.:
023139884
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
2,141,047 ** see Note 1 **
** Note 1 ** Dimensional Fund Advisors LP, an investment adviser registered under Section 203 of the Investment Advisors Act of 1940, furnishes investment advice to four investment companies registered under the Investment Company Act of 1940, and serves as investment manager or sub-adviser to certain other commingled funds, group trusts and separate accounts (such investment companies, trusts and accounts, collectively referred to as the "Funds"). In certain cases, subsidiaries of Dimensional Fund Advisors LP may act as an adviser or sub-adviser to certain Funds. In its role as investment advisor, sub-adviser and/or manager, Dimensional Fund Advisors LP or its subsidiaries (collectively, "Dimensional") may possess voting and/or investment power over the securities of the Issuer that are owned by the Funds, and may be deemed to be the beneficial owner of the shares of the Issuer held by the Funds. However, all securities reported in this schedule are owned by the Funds. Dimensional disclaims beneficial ownership of such securities. In addition, the filing of this Schedule 13G shall not be construed as an admission that the reporting person or any of its affiliates is the beneficial owner of any securities covered by this Schedule 13G for any other purposes than Section 13(d) of the Securities Exchange Act of 1934.
(b)
Percent of class:
4.6 %
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
2,094,221** see Note 1 **
(ii) Shared power to vote or to direct the vote:
0
(iii) Sole power to dispose or to direct the disposition of:
2,141,047** see Note 1 **
(iv) Shared power to dispose or to direct the disposition of:
0
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
The Funds described in Note 1 above have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of the securities held in their respective accounts. To the knowledge of Dimensional, the interest of any one such Fund does not exceed 5% of the class of securities. Dimensional Fund Advisors LP disclaims beneficial ownership of all such securities.
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
What stake does Dimensional Fund Advisors LP hold in Ambac (AMBC)?
Dimensional reports beneficial ownership of 2,141,047 shares, equal to 4.6% of Ambac's common stock as of 09/30/2025.
How many shares does Dimensional have voting power over for AMBC?
Dimensional reports sole voting power over 2,094,221 shares and sole dispositive power over 2,141,047 shares.
Does Dimensional claim beneficial ownership of the AMBC shares?
No. The filing states the shares are owned by client Funds and Dimensional disclaims beneficial ownership while reporting for regulatory purposes.
Was this filing made as a passive investor or to influence control?
The certification declares the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control.
When is the event date covered by this Schedule 13G amendment?
The date of the event requiring this filing is 09/30/2025, and the signature on the amendment is dated 10/09/2025.
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