Magnetar Reports 950,000‑Share (7.07%) Stake in Blue Water

Accepted by SEC EDGAR 05/13/2026 - 09:29 AM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Blue Water Acquisition Corp. IV Schedule 13G filing states that Magnetar Financial LLC, Magnetar Capital Partners LP, Supernova Management LLC and David J. Snyderman report shared beneficial ownership of 950,000 Class A ordinary shares, representing approximately 7.07% of outstanding shares. The filing attributes the shares to multiple Magnetar funds and lists a per‑fund breakdown. The filing cites an outstanding share base of 13,425,000 (per an issuer Form 8‑K). The Reporting Persons file jointly and disclose shared voting and dispositive power over the reported position.

Insights

Corporate Governance Analyst

Large passive stake disclosed with shared control across related entities.

The filing shows a collective 7.07% beneficial interest in Blue Water Acquisition Corp. IV held across several Magnetar funds, with shared voting and dispositive power over 950,000 shares as of March 31, 2026. The filing is a joint disclosure under Schedule 13G and identifies the chain of control through parent and general partner entities.

Implications depend on future filings: any change from passive to active investor status or amendments increasing ownership would be material. Subsequent disclosures may specify transactions or change in voting intent.

Fund Ownership Specialist

Position is distributed across multiple Magnetar funds; per‑fund holdings provided.

The filing lists per‑fund allocations: 228,000 (Constellation Master Fund), 161,500 (Lake Credit Fund), 209,000 (Structured Credit Fund), 152,000 (Xing He Master Fund), 161,500 (Alpha Star Fund), 9,500 (Capital Master Fund), and 28,500 (Waterfront Series A Fund). These amounts together are reported as shared beneficial ownership under common advisory and control relationships.

Watch for future amendments or Schedule 13D conversion filings that would signal an active strategy; current filing indicates passive reporting under Rule 13d‑1(c).

Key Figures

Reported shares owned: 950,000 shares Percent of class: 7.07% Outstanding shares (issuer): 13,425,000 shares +3 more

6 metrics

Reported shares owned 950,000 shares Total beneficially owned by each Reporting Person as of March 31, 2026

Percent of class 7.07% Percent of outstanding shares calculated under Rule 13d‑3(d)(1)(i)

Outstanding shares (issuer) 13,425,000 shares Issuer‑reported outstanding share count cited from Form 8‑K (March 19, 2026)

Constellation Master Fund holding 228,000 shares Part of the 950,000 total reported in the filing

Structured Credit Fund holding 209,000 shares Part of the 950,000 total reported in the filing

Lake Credit Fund holding 161,500 shares Part of the 950,000 total reported in the filing

Key Terms

Schedule 13G, beneficial ownership, shared dispositive power, Rule 13d-3(d)(1)(i), +1 more

5 terms

Schedule 13G regulatory

"This statement is filed on behalf of each of the following person (collectively, the "Reporting Persons")"

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.

beneficial ownership financial

"As of March 31, 2026, each of Magnetar Financial... held 950,000 Shares"

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.

shared dispositive power regulatory

"Shared Dispositive Power 950,000.00"

Rule 13d-3(d)(1)(i) regulatory

"represent approximately 7.07% of the total number of Shares outstanding (calculated pursuant to Rule 13d-3(d)(1)(i))"

Joint Filing Agreement regulatory

"Exhibit Information 99.1 Joint Filing Agreement, dated as of May 13, 2026"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does Magnetar report in Blue Water Acquisition (BWIV)?

Magnetar reports beneficial ownership of 950,000 shares, about 7.07%. The filing states this total across multiple Magnetar funds, calculated using an issuer‑reported outstanding share count of 13,425,000 from an earlier Form 8‑K.

How is the 950,000‑share position allocated among Magnetar funds?

The filing gives a per‑fund breakdown totaling 950,000 shares. Examples: 228,000 (Constellation Master Fund) and 209,000 (Structured Credit Fund). Other funds and smaller allocations complete the total as listed in the filing.

Do the Reporting Persons have sole voting or dispositive power over these shares?

No sole power is reported. The Schedule 13G states the Reporting Persons have shared power to vote and dispose of 950,000 shares and no sole voting or dispositive power for the reported shares.

What does the Schedule 13G filing imply about Magnetar's intent?

Schedule 13G filings generally indicate passive investment reporting. The filing identifies shared beneficial ownership and joint filing status; it does not state an intent to influence control or active plans in this excerpt.

What outstanding share count does the filing use to calculate 7.07%?

The filing cites approximately 13,425,000 shares outstanding. That figure is attributed to the issuer's Form 8‑K referenced in the Schedule 13G and is used to compute the reported 7.07% ownership percentage.

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

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

BLUE WATER ACQUISITION CORP. IV

(Name of Issuer)

Class A ordinary shares, par value $0.0001

(Title of Class of Securities)

G1368A120

(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): G1368A120

1

Names of Reporting Persons

MAGNETAR FINANCIAL LLC

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 950,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 950,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

950,000.00

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)

7.07 %

12

Type of Reporting Person (See Instructions)

IA, OO

SCHEDULE 13G

CUSIP Number(s): G1368A120

1

Names of Reporting Persons

MAGNETAR CAPITAL PARTNERS 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 950,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 950,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

950,000.00

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)

7.07 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): G1368A120

1

Names of Reporting Persons

SUPERNOVA MANAGEMENT LLC

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 950,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 950,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

950,000.00

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)

7.07 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP Number(s): G1368A120

1

Names of Reporting Persons

DAVID J. SNYDERMAN

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 950,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 950,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

950,000.00

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)

7.07 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: BLUE WATER ACQUISITION CORP. IV
(b)	Address of issuer's principal executive offices: 15 E. Putnam Avenue, Suite 363, Greenwich, CT 06830
Item 2.
(a)	Name of person filing: This statement is filed on behalf of each of the following person (collectively, the "Reporting Persons"): i) Magnetar Financial LLC ("Magnetar Financial"); ii) Magnetar Capital Partners LP ("Magnetar Capital Partners"); iii) Supernova Management LLC ("Supernova Management"); and iv) David J. Snyderman ("Mr. Snyderman"). This statement relates to the Shares (as defined herein) held for Magnetar Constellation Master Fund, Ltd ("Constellation Master Fund"), Magnetar Xing He Master Fund Ltd ("Xing He Master Fund"), Magnetar Capital Master Fund Ltd ("Capital Master Fund"), all Cayman Islands exempted companies; Magnetar Structured Credit Fund, LP ("Structured Credit Fund"), a Delaware limited partnership; Magnetar Alpha Star Fund LLC ("Alpha Star Fund"), Magnetar Lake Credit Fund LLC ("Lake Credit Fund"), and Magnetar Waterfront Series A LLC ("Waterfront Series A Fund"), all Delaware limited liability companies; collectively (the "Magnetar Funds"). Magnetar Financial serves as the investment adviser to the Magnetar Funds, and as such, Magnetar Financial exercises voting and investment power over the Shares held for the Magnetar Funds' accounts. Magnetar Capital Partners serves as the sole member and parent holding company of Magnetar Financial. Supernova Management is the general partner of Magnetar Capital Partners. The administrative manager of Supernova Management is Mr. Snyderman.
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of Magnetar Financial, Magnetar Capital Partners, Supernova Management, and Mr. Snyderman is 1603 Orrington Avenue, 13th Floor, Evanston, Illinois 60201.
(c)	Citizenship: Place of Organization. i) Magnetar Financial is a Delaware limited liability company; ii) Magnetar Capital Partners is a Delaware limited partnership; iii) Supernova Management is a Delaware limited liability company; and iv) Mr. Snyderman is a citizen of the United States of America.
(d)	Title of class of securities: Class A ordinary shares, par value $0.0001
(e)	CUSIP Number(s): G1368A120
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: As of March 31, 2026, each of Magnetar Financial, Magnetar Capital Partners, Supernova Management and Mr. Snyderman held 950,000 Shares. The amount consists of (A) 228,000 Shares held for the account of Constellation Master Fund; (B) 161,500 Shares held for the account of Lake Credit Fund; (C) 209,000 Shares held for the account of Structured Credit Fund; (D) 152,000 Shares held for the account of Xing He Master Fund; (E) 161,500 Shares held for the account of Alpha Star Fund; (F) 9,500 Shares held for the account of Capital Master Fund; and (G) 28,500 shares held for the account of Waterfront Series A Fund. The Shares held by the Magnetar Funds represent approximately 7.07% of the total number of Shares outstanding (calculated pursuant to Rule 13d-3(d)(1)(i)) of the outstanding shares of the Issuer).
(b)	Percent of class: As of March 31, 2026, each of the Reporting Persons were deemed to be the beneficial owner constituting approximately 7.07% of the total number of shares outstanding (based upon the information provided by the Issuer in the Form 8-K filed on March 19, 2026 there were approximately 13,425,000 Shares outstanding).
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 950,000
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 950,000
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.
	Not Applicable
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.

MAGNETAR FINANCIAL LLC

Signature:	/s/ Hayley Stein
Name/Title:	Name: Hayley Stein, Title: Attorney-in-fact for David J. Snyderman, Administrative Manager of Supernova Management LLC
Date:	05/13/2026

MAGNETAR CAPITAL PARTNERS LP

Signature:	/s/ Hayley Stein
Name/Title:	Name: Hayley Stein, Title: Attorney-in-fact for David J. Snyderman, Administrative Manager of Supernova Management LLC
Date:	05/13/2026

SUPERNOVA MANAGEMENT LLC

Signature:	/s/ Hayley Stein
Name/Title:	Name: Hayley Stein, Title: Attorney-in-fact for David J. Snyderman, Administrative Manager of Supernova Management LLC
Date:	05/13/2026

DAVID J. SNYDERMAN

Signature:	/s/ Hayley Stein
Name/Title:	Name: Hayley Stein, Title: Attorney-in-fact for David J. Snyderman, Administrative Manager of Supernova Management LLC
Date:	05/13/2026

Comments accompanying signature: MAGNETAR FINANCIAL LLC BY: Magnetar Capital Partners LP, its Sole Member BY: Supernova Management LLC, its General Partner MAGNETAR CAPITAL PARTNERS LP By: Supernova Management LLC, its General Partner

Exhibit Information

99.1 Joint Filing Agreement, dated as of May 13, 2026, among the Reporting Persons. 99.2 Power of Attorney, dated as of December 22, 2022 filed by the Reporting Persons on May 13, 2026.