Adage Capital reports a 7.82% passive stake in FG Imperii Acquisition Corp. The filing states Adage Capital Management, L.P., together with Robert Atchinson and Phillip Gross, beneficially hold 1,800,000 Class A ordinary shares representing 7.82% of the class based on March 31, 2026 outstanding share count of 23,025,000. The shares are reported as held by Adage entities with shared voting and dispositive power of 1,800,000 shares.
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Insights
Adage reports a passive, >5% holding in FG Imperii (7.82%).
Adage Capital Management, L.P., together with named principals, reports beneficial ownership of 1,800,000 shares, equal to 7.82% of class based on an outstanding base of March 31, 2026. The filing is a Schedule 13G disclosure showing shared voting and dispositive power.
Because the filing is a passive ownership statement rather than an acquisition or disposition notice, cash‑flow treatment and planned actions are not disclosed; subsequent filings would show any trading activity or changes in ownership.
Filing clarifies ownership structure and attribution to Adage entities and principals.
The statement attributes the 1,800,000 shares to Adage Capital entities and names Robert Atchinson and Phillip Gross as reporting persons with shared voting/dispositive authority. The calculation cites the issuer's 10-K outstanding share count.
Reporting notes that disclosures are made on information and belief; any voting coordination or future changes would require separate filings.
Key Figures
Shares beneficially owned:1,800,000 sharesPercent of class:7.82%Shares outstanding:23,025,000 shares
3 metrics
Shares beneficially owned1,800,000 sharesreported by Adage and principals
Percent of class7.82%based on outstanding shares as of <date>March 31, 2026</date>
Shares outstanding23,025,000 sharesissuer's Form 10-K as of <date>March 31, 2026</date>
"This statement is filed by: (i) Adage Capital Management, L.P."
A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.
Shared voting powercorporate
"Shared Voting Power 1,800,000.00"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
Beneficial ownershipregulatory
"Amount beneficially owned: The information required by Item 4(a)"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
FG Imperii Acquisition Corp.
(Name of Issuer)
Class A ordinary shares, par value $0.0001
(Title of Class of Securities)
G3R41C102
(CUSIP Number)
03/31/2026
(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)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
G3R41C102
1
Names of Reporting Persons
Adage Capital Management, L.P.
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
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,800,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,800,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,800,000.00
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)
7.82 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
G3R41C102
1
Names of Reporting Persons
Robert Atchinson
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
0.00
6
Shared Voting Power
1,800,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,800,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,800,000.00
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)
7.82 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
CUSIP Number(s):
G3R41C102
1
Names of Reporting Persons
Phillip Gross
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
0.00
6
Shared Voting Power
1,800,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,800,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,800,000.00
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)
7.82 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
FG Imperii Acquisition Corp.
(b)
Address of issuer's principal executive offices:
104 S. Walnut Street, Unit 1A, Itasca, Illinois 60143
Item 2.
(a)
Name of person filing:
This statement is filed by:
(i) Adage Capital Management, L.P., a Delaware limited partnership ("ACM"), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership ("ACP"), with respect to the Class A ordinary shares, par value $0.0001 ("Class A Ordinary Shares") of FG Imperii Acquisition Corp., a Cayman Islands exempted company (the "Company") directly held by ACP;
(ii) Robert Atchinson ("Mr. Atchinson"), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACA"), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACPGP"), general partner of ACP, and (2) managing member of Adage Capital Partners, L.L.C., a Delaware limited liability company ("ACPLLC"), general partner of ACM, with respect to the Class A Ordinary Shares directly held by ACP; and
(iii) Phillip Gross ("Mr. Gross"), as (1) managing member of ACA, managing member of ACPGP, and (2) managing member of ACPLLC, general partner of ACM, with respect to the Class A Ordinary Shares directly held by ACP.
The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party.
The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of the securities reported herein.
(b)
Address or principal business office or, if none, residence:
The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.
(c)
Citizenship:
ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States.
(d)
Title of class of securities:
Class A ordinary shares, par value $0.0001
(e)
CUSIP Number(s):
G3R41C102
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:
The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 23,025,000 Class A Ordinary Shares outstanding as of March 31, 2026, as reported in the Company's Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission on March 31, 2026.
(b)
Percent of class:
7.82%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
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.
See Item 2(a).
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.
Adage Capital Management, L.P.
Signature:
/s/ Robert Atchinson
Name/Title:
By: Adage Capital Partners, L.L.C., its General Partner, By: Robert Atchinson, its Managing Member
What stake does Adage Capital hold in FG Imperii (FGII)?
Adage Capital and the reporting persons beneficially hold 1,800,000 Class A ordinary shares, equal to 7.82% of the class based on March 31, 2026 and 23,025,000 shares outstanding.
Who are the reporting persons on the Schedule 13G for FGII?
The filing is made by Adage Capital Management, L.P. and individual reporting persons Robert Atchinson and Phillip Gross, each disclosed in their roles with Adage entities and as managing members.
How is voting and dispositive power described in the FGII filing?
The Schedule 13G reports shared voting power and shared dispositive power of 1,800,000 shares for the reporting persons; sole powers are reported as 0 on the cover page.
What outstanding share count does the FGII filing use to calculate percent ownership?
The percent ownership is calculated using an aggregate outstanding share count of 23,025,000 Class A Ordinary Shares reported as of March 31, 2026 in the issuer's Form 10-K.
Does the Schedule 13G indicate intent to buy or sell FGII shares?
No. The Schedule 13G is a passive ownership disclosure and does not state any purchase or sale intentions; the filing does not disclose planned transactions or cash‑flow treatment.
