SilverBox Corp IV: Calamos fund holds 7.8% stake

The fund reports sole voting and dispositive authority over its 7.8% Class A position.

Rhea-AI Filing Summary

SilverBox Corp IV’s Class A ownership disclosure lists Calamos Market Neutral Income Fund, a series of Calamos Investment Trust, as beneficially owning 500,000 shares, or 7.8% of the class. The fund reports sole voting and dispositive power over 500,000 shares, with zero shared voting or dispositive power.

Key Figures

Beneficially owned: 500,000 shares Percent of class: 7.8% Sole voting power: 500,000 shares +3 more

6 metrics

Beneficially owned 500,000 shares Calamos Market Neutral Income Fund

Percent of class 7.8% SilverBox Corp IV Class A

Sole voting power 500,000 shares Calamos Market Neutral Income Fund

Shared voting power 0 shares Calamos Market Neutral Income Fund

Sole dispositive power 500,000 shares Calamos Market Neutral Income Fund

Shared dispositive power 0 shares Calamos Market Neutral Income Fund

Key Terms

Amount beneficially owned, Sole Voting Power, Sole Dispositive Power

3 terms

Amount beneficially owned financial

"Amount beneficially owned: 500,000"

Sole Voting Power financial

"Sole Voting Power 500,000.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Sole Dispositive Power financial

"Sole Dispositive Power 500,000.00"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

FAQ

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

How many SBXD Class A shares does Calamos Market Neutral Income Fund own?

Calamos Market Neutral Income Fund beneficially owns 500,000 SilverBox Corp IV Class A shares, representing 7.8% of the class. It reports sole voting and dispositive power over those shares.

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

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Available on EDGAR 10/09/2026 - 09:23 AM EDT Accepted by SEC EDGAR 10/09/2026 - 09:22 AM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

SilverBox Corp IV

(Name of Issuer)

Class A

(Title of Class of Securities)

G81354105

(CUSIP Number)

09/30/2026

(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): G81354105

1

Names of Reporting Persons

Calamos Market Neutral Income Fund, a series of Calamos Investment Trust

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

MASSACHUSETTS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 500,000.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 500,000.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

500,000.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

IV

SCHEDULE 13G

Item 1.
(a)	Name of issuer: SilverBox Corp IV
(b)	Address of issuer's principal executive offices: 1250 South Capital of Texas Highway, Building 2, Suite 285, Austin, TX 78746
Item 2.
(a)	Name of person filing: Calamos Market Neutral Income Fund, a series of Calamos Investment Trust
(b)	Address or principal business office or, if none, residence: 2020 Calamos Ct Naperville, IL 60563
(c)	Citizenship: Massachusetts, U.S.A.
(d)	Title of class of securities: Class A
(e)	CUSIP Number(s): G81354105
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: 500,000
(b)	Percent of class: 7.8%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 500,000
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 500,000
	(iv) Shared power to dispose or to direct the disposition of: 0
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:
	Not Applicable

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.

Calamos Market Neutral Income Fund, a series of Calamos Investment Trust

Signature:	/s/ Erik D. Ojala
Name/Title:	Erik D. Ojala, Senior Vice President, Secretary
Date:	10/07/2026