Adage Capital discloses 1.13M AmperCap (APMC) shares, a 5.64% ownership stake

Rhea-AI Filing Summary

Adage Capital Management, L.P., together with Robert Atchinson and Phillip Gross, reports beneficial ownership of 1,125,000 Ordinary Shares of AmperCap Acquisition Company. These Ordinary Shares have a par value of $0.0001 per share.

The stake represents 5.64% of the outstanding class, based on 19,958,575 Ordinary Shares outstanding after AmperCap’s offering, simultaneous private placement, partial exercise of the underwriters’ over-allotment option, and forfeiture of 13,217 shares, as referenced in the company’s prospectus and a subsequent current report. The Reporting Persons share both voting and dispositive power over these shares and disclaim that this filing alone constitutes an admission of beneficial ownership beyond what is reported.

Key Figures

Shares beneficially owned: 1,125,000 Ordinary Shares Ownership percentage: 5.64% Shares outstanding: 19,958,575 Ordinary Shares +2 more

5 metrics

Shares beneficially owned 1,125,000 Ordinary Shares Ordinary Shares of AmperCap Acquisition Company reported by the Reporting Persons

Ownership percentage 5.64% Percent of AmperCap Ordinary Shares outstanding held by the Reporting Persons

Shares outstanding 19,958,575 Ordinary Shares Aggregate Ordinary Shares outstanding after offering, private placement, over-allotment and forfeiture

Par value per share $0.0001 per share Par value of AmperCap Acquisition Company Ordinary Shares

Forfeited shares 13,217 Ordinary Shares Ordinary Shares forfeited in connection with offering-related transactions

Key Terms

beneficial ownership, Schedule 13G, investment manager, over-allotment option, +1 more

5 terms

beneficial ownership financial

"The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership"

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.

Schedule 13G regulatory

"Ownership of more than 5 Percent on Behalf of Another Person."

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.

investment manager financial

"ACM, as the investment manager of Adage Capital Partners, L.P."

over-allotment option financial

"after giving effect to ... the partial exercise of the underwriters' over-allotment option"

An over-allotment option is a special agreement that allows underwriters to sell more shares than initially planned if demand is high. Think of it like a retailer offering extra units of a popular product to meet additional customer interest. This option helps ensure the full sale is completed and can also give investors extra shares if they want more.

simultaneous private placement financial

"after giving effect to ... the consummation of the simultaneous private placement"

FAQ

What percentage of AmperCap Acquisition Company (APMC) does Adage Capital report owning?

Adage Capital and related Reporting Persons report beneficial ownership of 5.64% of AmperCap Acquisition Company’s Ordinary Shares. This percentage is calculated from 19,958,575 shares outstanding after the company’s offering, private placement, over-allotment exercise, and share forfeiture.

How many AmperCap (APMC) shares are beneficially owned by the Reporting Persons?

The Reporting Persons report beneficial ownership of 1,125,000 Ordinary Shares of AmperCap Acquisition Company. They have shared voting and shared dispositive power over these shares and no sole voting or dispositive power.

Who are the Reporting Persons in the AmperCap (APMC) Schedule 13G filing?

The Reporting Persons are Adage Capital Management, L.P., Robert Atchinson, and Phillip Gross. Adage acts as investment manager to Adage Capital Partners, L.P., which directly holds the AmperCap shares reported in this Schedule 13G.

What is the share count used to calculate Adage’s 5.64% stake in APMC?

The 5.64% ownership stake is calculated using 19,958,575 Ordinary Shares outstanding. This figure reflects AmperCap’s post-offering share count, including the private placement, partial over-allotment exercise, and forfeiture of 13,217 shares.

Where are the Reporting Persons in the APMC Schedule 13G based?

The principal business office of each Reporting Person is at 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116. Adage Capital Management is organized under Delaware law; Messrs. Atchinson and Gross are citizens of the United States.

Does the AmperCap (APMC) Schedule 13G indicate shared or sole voting power?

The filing reports 0 shares with sole voting or dispositive power and 1,125,000 shares with shared voting and shared dispositive power among the Reporting Persons. This reflects coordinated control over the reported position.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/12/2026 - 12:02 PM Accepted by SEC EDGAR 08/12/2026 - 12:02 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

AmperCap Acquisition Company

(Name of Issuer)

Ordinary Shares, par value $0.0001 per share

(Title of Class of Securities)

G0344N107

(CUSIP Number)

06/30/2026

(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): G0344N107

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 1,125,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,125,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,125,000.00

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)

5.64 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP Number(s): G0344N107

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 1,125,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,125,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,125,000.00

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)

5.64 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP Number(s): G0344N107

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 1,125,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,125,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,125,000.00

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)

5.64 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: AmperCap Acquisition Company
(b)	Address of issuer's principal executive offices: 12 East 49th Street, 18th Floor, New York NY 10017
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 ordinary shares, par value $0.0001 per share ("Ordinary Shares") of AmperCap Acquisition Company, 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 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 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: Ordinary Shares, par value $0.0001 per share
(e)	CUSIP Number(s): G0344N107
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 19,958,575 Ordinary Shares outstanding, as reported in the Company's Prospectus filed pursuant to Rule 424(b)(4) with the Securities and Exchange Commission on June 3, 2026 and the Company's Current Report on Form 8-K filed with the Securities and Exchange Commission on June 18, 2026, after giving effect to the completion of the offering, the consummation of the simultaneous private placement, the partial exercise of the underwriters' over-allotment option and the forfeiture of 13,217 Ordinary Shares, all as described therein.
(b)	Percent of class: 5.64%
(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
Date:	08/12/2026

Robert Atchinson

Signature:	/s/ Robert Atchinson
Name/Title:	Robert Atchinson, individually
Date:	08/12/2026

Phillip Gross

Signature:	/s/ Phillip Gross
Name/Title:	Phillip Gross, individually
Date:	08/12/2026

Exhibit Information

Exhibit 99.1: Joint Filing Agreement