Magnetar discloses 2.0M shares (5.40%) of MLAA

Magnetar-affiliated holders report beneficial ownership of 2,000,000 Class A ordinary shares of Mountain Lake Acquisition Corp. II.

Accepted by SEC EDGAR 05/13/2026 - 09:50 AM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Magnetar-affiliated holders report beneficial ownership of 2,000,000 Class A ordinary shares of Mountain Lake Acquisition Corp. II. As of March 31, 2026, the filing states the 2,000,000 shares represent approximately 5.40% of the outstanding shares. The filing attributes shared voting and shared dispositive power over those shares to the Reporting Persons and lists the fund-level allocation by account.

The statement cites an issuer-provided outstanding share count of 36,980,000 shares from a Form 10-K filed on March 20, 2026. The disclosure is a passive ownership report under Schedule 13G and is signed by an attorney-in-fact on behalf of the Reporting Persons.

Insights

Securities Governance Specialist

Schedule 13G confirms passive, shared beneficial ownership disclosure.

The filing lists 2,000,000 shares held by Magnetar-related entities and individuals, representing 5.40% of outstanding stock as of March 31, 2026. It attributes shared voting and dispositive power and provides a per-fund allocation totaling the same share count.

This report is procedural: subsequent filings would reflect any change in status or percent ownership; timing for such updates is governed by the securities rules applicable to Schedule 13G filers.

Securities Compliance Counsel

Disclosure aligns with beneficial-ownership reporting mechanics under Rule 13d.

The statement references Rule 13d-3(d)(1)(i) for the percentage calculation and cites an issuer-provided outstanding share number from a Form 10-K. It identifies the relationships among Magnetar Financial, Magnetar Capital Partners, Supernova Management, and an individual administrator.

Signatures and the joint filing agreement exhibit are attached; filings should be monitored for any material change that would require an amended filing under the applicable rules.

Key Figures

Beneficial ownership: 2,000,000 shares Ownership percentage: 5.40% Shares outstanding (issuer cited): 36,980,000 shares +2 more

5 metrics

Beneficial ownership 2,000,000 shares As of March 31, 2026; held by Magnetar Reporting Persons

Ownership percentage 5.40% Calculated under Rule 13d-3(d)(1)(i) using issuer data

Shares outstanding (issuer cited) 36,980,000 shares From Form 10-K filed March 20, 2026; used for percentage calculation

Constellation Master Fund allocation 460,000 shares Part of the 2,000,000-share total held for Magnetar funds

Structured Credit Fund allocation 420,000 shares Part of the 2,000,000-share total held for Magnetar funds

Key Terms

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

4 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 2,000,000 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 2,000,000.00"

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

"represent approximately 5.40% of the total number of Shares outstanding (calculated pursuant to Rule 13d-3(d)(1)(i))"

FAQ

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

What stake does Magnetar report in MLAA?

Magnetar-affiliated Reporting Persons report beneficial ownership of 2,000,000 shares, representing 5.40% of Class A ordinary shares as of March 31, 2026. The filing lists per-fund allocations summing to that amount.

How was the 5.40% ownership percentage calculated for MLAA?

The percentage uses the issuer-provided outstanding share count of 36,980,000 shares cited from the Form 10-K filed on March 20, 2026. The filing references Rule 13d-3(d)(1)(i) for the calculation method.

Who holds voting and dispositive power over the reported shares?

The filing states the Reporting Persons have shared voting power and shared dispositive power over the 2,000,000 shares, with no sole voting or sole dispositive power listed in the disclosure.

Which Magnetar funds account for the 2,000,000 shares?

The filing allocates the shares across funds: Constellation Master Fund 460,000, Lake Credit Fund 340,000, Structured Credit Fund 420,000, Xing He Master Fund 300,000, Alpha Star Fund 340,000, plus smaller allocations totaling 2,000,000 shares.

Does this Schedule 13G indicate active control or a sale?

The disclosure reports beneficial ownership and shared power; it does not state any transaction, sale, or acquisition. The filing is a passive ownership report and does not indicate active disposition in this excerpt.

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

MOUNTAIN LAKE ACQUISITION CORP. II

(Name of Issuer)

Class A ordinary shares, par value $0.0001

(Title of Class of Securities)

G6301L109

(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): G6301L109

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 2,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,000,000.00

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)

5.40 %

12

Type of Reporting Person (See Instructions)

IA, OO

SCHEDULE 13G

CUSIP Number(s): G6301L109

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 2,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,000,000.00

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)

5.40 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): G6301L109

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 2,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,000,000.00

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)

5.40 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP Number(s): G6301L109

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 2,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,000,000.00

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)

5.40 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MOUNTAIN LAKE ACQUISITION CORP. II
(b)	Address of issuer's principal executive offices: 930 Tahoe Blvd, Ste 802 PMB45, Incline Village, NV 89451
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"), Purpose Alternative Credit Fund - T LLC ("Purpose Alternative Credit Fund - T"), 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): G6301L109
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 2,000,000 Shares. The amount consists of (A) 460,000 Shares held for the account of Constellation Master Fund; (B) 340,000 Shares held for the account of Lake Credit Fund; (C) 420,000 Shares held for the account of Structured Credit Fund; (D) 300,000 Shares held for the account of Xing He Master Fund; (E) 340,000 Shares held for the account of Alpha Star Fund; (F) 20,000 Shares held for the account of Capital Master Fund; (G) 60,000 shares held for the account of Waterfront Series A Fund; and (H) 60,000 Shares held for the account Purpose Alternative Credit Fund - T. The Shares held by the Magnetar Funds represent approximately 5.40% 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 5.40% of the total number of shares outstanding (based upon the information provided by the Issuer in the Form 10-K filed on March 20, 2026 there were approximately 36,980,000 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: 2,000,000
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 2,000,000
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 14, 2026, among the Reporting Persons. 99.2 Power of Attorney, dated as of December 22, 2022 filed by the Reporting Persons on May 14, 2026.