SIM Acquisition Corp. I holder Magnetar at 0%

Rhea-AI Filing Summary

SIM Acquisition Corp. I (SIMA) received an amended Schedule 13G filing (Amendment No. 1) in which Magnetar Financial LLC, Magnetar Capital Partners LP, Supernova Management LLC, and David J. Snyderman report that, as of June 30, 2026, they collectively beneficially owned 0 shares of SIMA common stock.

The reporting group states it now has 0% beneficial ownership of SIMA’s common stock, with no sole or shared voting or dispositive power over any shares, indicating its position has fallen to or remains at 5% or less of the class.

Key Figures

Beneficially owned shares: 0 shares Percent of class owned: 0% Sole voting power: 0 shares +1 more

4 metrics

Beneficially owned shares 0 shares SIMA common stock beneficially owned by each reporting person as of June 30, 2026

Percent of class owned 0% Approximate percentage of SIMA common stock class owned by the reporting persons as of June 30, 2026

Sole voting power 0 shares Shares of SIMA over which each reporting person has sole power to vote

Shared voting power 0 shares Shares of SIMA over which each reporting person has shared power to vote

Key Terms

beneficial owner, Rule 13d-3(d)(1)(i), Ownership of 5 percent or less of a class, Power of Attorney, +1 more

5 terms

beneficial owner financial

"each of the Reporting Persons were deemed to be the beneficial owner"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

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

"calculated pursuant to Rule 13d-3(d)(1)(i) of the outstanding shares"

Ownership of 5 percent or less of a class regulatory

"Item 5. | Ownership of 5 percent or less of a class."

Power of Attorney regulatory

"99.2 Power of Attorney, dated as of December 22, 2022"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

Joint Filing Agreement regulatory

"99.1 Joint Filing Agreement, dated as of September 4, 2026"

FAQ

What does this Schedule 13G/A disclose about SIMA share ownership by Magnetar entities?

It discloses that, as of June 30, 2026, Magnetar Financial LLC, Magnetar Capital Partners LP, Supernova Management LLC, and David J. Snyderman beneficially owned 0 SIMA common shares, representing 0% of the outstanding class, with no voting or dispositive power over any shares.

Who are the reporting persons in this SIMA Schedule 13G/A filing?

The reporting persons are Magnetar Financial LLC, Magnetar Capital Partners LP, Supernova Management LLC, and David J. Snyderman. Magnetar Financial serves as investment adviser to certain Magnetar funds, and the other entities sit above it in the ownership structure.

What percentage of SIMA common stock do the reporting persons now own?

They report beneficial ownership of approximately 0% of SIM Acquisition Corp. I’s common stock. The filing states that the shares held for the Magnetar funds’ accounts represent approximately 0% of SIMA’s total shares outstanding, calculated under Rule 13d-3(d)(1)(i).

Do the reporting persons have any voting or dispositive power over SIMA shares?

No. The filing states that each reporting person has 0 shares with sole power to vote, 0 shares with shared power to vote, 0 shares with sole power to dispose, and 0 shares with shared power to dispose of SIMA common stock.

What addresses are listed for SIMA and the reporting persons in this 13G/A?

SIM Acquisition Corp. I’s principal executive offices are at 725 Fifth Ave, 22nd Floor, New York, NY 10022. The principal business office for Magnetar Financial, Magnetar Capital Partners, Supernova Management, and David J. Snyderman is 1603 Orrington Avenue, 13th Floor, Evanston, Illinois 60201.

Who signed the SIMA Schedule 13G/A on behalf of the reporting persons?

The filing is signed by Hayley Stein, identified as attorney-in-fact for David J. Snyderman, the administrative manager of Supernova Management LLC. Signatures for the entities reflect their internal chain of authority, including Magnetar Capital Partners LP and Supernova Management LLC.

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

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Available on EDGAR 09/04/2026 - 09:04 AM Accepted by SEC EDGAR 09/04/2026 - 09:02 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

SIM ACQUISITION CORP. I

(Name of Issuer)

Common Stock, par value $0.0001

(Title of Class of Securities)

G8431T101

(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): G8431T101

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0 %

12

Type of Reporting Person (See Instructions)

IA, OO

SCHEDULE 13G

CUSIP Number(s): G8431T101

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): G8431T101

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP Number(s): G8431T101

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: SIM ACQUISITION CORP. I
(b)	Address of issuer's principal executive offices: 725 Fifth Ave, 22nd Floor, New York, NY 10022
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"). 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: Common Stock, par value $0.0001
(e)	CUSIP No.: G8431T101
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 June 30, 2026, each of Magnetar Financial, Magnetar Capital Partners, Supernova Management and Mr. Snyderman held 0 Shares. The Shares held by the Magnetar Funds represent approximately 0% 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 June 30, 2026, each of the Reporting Persons were deemed to be the beneficial owner constituting approximately 0% of the total number of 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: 0
	(iii) Sole power to dispose or to direct the disposition of: 0
	(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.
	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:	09/04/2026

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:	09/04/2026

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:	09/04/2026

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:	09/04/2026

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 September 4, 2026, among the Reporting Persons. 99.2 Power of Attorney, dated as of December 22, 2022 filed by the Reporting Persons on September 4, 2026.