[SCHEDULE 13G/A] Calamos Strategic Total Return Fund SEC Filing

Rhea-AI Filing Summary

The filing is an amendment to a Schedule 13G reporting that a group of related Apollo entities and Athene Annuity and Life Company collectively hold 1,920,000 Series F Mandatory Redeemable Preferred Shares of Calamos Strategic Total Return Fund. That holding represents 48.0% of the 4,000,000 MRPS outstanding (per the issuer's certified shareholder report dated April 30, 2025). No reporting person claims sole voting or dispositive power; each reports zero sole power and shared voting and dispositive power over 1,920,000 shares. The filing states the securities were acquired and are held in the ordinary course of business and not to change or influence control of the issuer.

Positive

• Material stake disclosed: Reporting Persons collectively hold 1,920,000 MRPS, representing 48.0% of the class
• Clear ownership breakdown: Each reporting person reports shared voting and dispositive power with zero sole power
• Compliance and certification: Filing includes required entity identifications, addresses and signed certifications dated 08/14/2025

Negative

• None.

Insights

Financial Analyst

TL;DR A coordinated group of Apollo entities and Athene own a near-majority 48% stake in the Series F preferreds, creating material influence potential.

The Schedule 13G/A shows a large, concentrated position: 1,920,000 MRPS representing 48% of the class. All reporting persons disclaim sole ownership and report shared voting and dispositive power only. For investors, concentrated preferred-holdings at this scale can affect liquidity and negotiation dynamics for the preferred class, though the filing expressly disclaims acquisition for control. The ownership percentage is calculated from 4,000,000 shares outstanding as of April 30, 2025, per the issuer's certified report.

Corporate Governance Expert

TL;DR A related-party group holds substantial preferred-class power, which is material for governance and creditor-preference considerations.

The report lists multiple interrelated entities (investment adviser, general partners, holding companies) that collectively report shared voting and dispositive power over 1,920,000 MRPS. While the signatories disclaim a purpose to change control and indicate ordinary-course holdings, the concentration across related entities is material to governance and potential future transactions involving the preferred class. The filing includes addresses and entity classifications consistent with standard disclosure practice.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 6)

Calamos Strategic Total Return Fund

(Name of Issuer)

Series F Mandatory Redeemable Preferred Shares

(Title of Class of Securities)

128125*60

(CUSIP Number)

06/30/2025

(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)

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo Management Holdings GP, 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 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Athene Annuity and Life Company

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

IOWA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

IC

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo Insurance Solutions Group 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 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

AISG GP Ltd.

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

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo Life Asset 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 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo Life Asset GP, 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

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo 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 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo Capital Management GP, 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 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. 128125*60

1

Names of Reporting Persons

Apollo Management Holdings, 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 1,920,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,920,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,920,000.00

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)

48.0 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Calamos Strategic Total Return Fund
(b)	Address of issuer's principal executive offices: 2020 Calamos Court C/o Calamos Advisors LLC Naperville, IL, 60563
Item 2.
(a)	Name of person filing: This statement is filed by: (i) Athene Annuity and Life Company ("AAIA"); (ii) Apollo Insurance Solutions Group LP ("AISG"); (iii) AISG GP Ltd. ("AISG GP"); (iv) Apollo Life Asset, L.P. ("Apollo Life"); (v) Apollo Life Asset GP, LLC ("Apollo Life GP"); (vi) Apollo Capital Management, L.P. ("Capital Management"); (vii) Apollo Capital Management GP, LLC ("Capital Management GP"); (viii) Apollo Management Holdings, L.P. ("Management Holdings"); and (ix) Apollo Management Holdings GP, LLC ("Management Holdings GP"). The foregoing are collectively referred to herein as the "Reporting Persons." AAIA holds Series F Mandatory Redeemable Preferred Shares (the "MRPS") of the Issuer. AISG is the investment adviser of AAIA. AISG GP is the general partner of AISG. Apollo Life is the general partner of AISG GP, and Apollo Life GP is the general partner of Apollo Life. Capital Management is the sole member of Apollo Life GP. The general partner of Capital Management is Capital Management GP. Management Holdings is the sole member and manager of Capital Management GP, and Management Holdings GP is the general partner of Management Holdings.
(b)	Address or principal business office or, if none, residence: The address of the principal office of AAIA is 7700 Mills Civic Parkway, West Des Moines, Iowa 50266. The address of the principal office of AISG is 2121 Rosecrans Ave., Ste 5300, El Segundo, California 90245. The address of the principal office of each of AISG GP and Apollo Life GP is c/o Walkers Corporate Limited, 190 Elgin Avenue, George Town, KY1-9008 Grand Cayman, Cayman Islands. The address of the principal office of each of Apollo Life, Capital Management, Capital Management GP, Management Holdings, and Management Holdings GP is 9 West 57th Street, 41st Floor, New York, NY 10019.
(c)	Citizenship: AAIA Iowa AISG Delaware AISG GP Cayman Islands Apollo Life Delaware Apollo Life GP Cayman Islands Capital Management Delaware Capital Management GP Delaware Management Holdings Delaware Management Holdings GP Delaware
(d)	Title of class of securities: Series F Mandatory Redeemable Preferred Shares
(e)	CUSIP No.: 128125*60
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: Information in Rows 5 to 11 of the respective cover pages of the individual Reporting Persons are incorporated into this Item 4 by reference. AISG, AISG GP, Apollo Life, Apollo Life GP, Capital Management, Capital Management GP, Management Holdings, and Management Holdings GP each disclaim beneficial ownership of all Common Stock included in this report, and the filing of this report shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities for purposes of Section 13(d) or 13(g) of the Securities Exchange Act of 1934, as amended, or for any other purpose.
(b)	Percent of class: Information in Rows 5 to 11 of the respective cover pages of the individual Reporting Persons are incorporated into this Item 4 by reference. The Reporting Persons' aggregate percentage of beneficial ownership of the total amount of MRPS outstanding is based on 4,000,000 shares of the MRPS outstanding as of April 30, 2025, as reported by the Issuer in its certified shareholder report filed with the Securities and Exchange Commission on June 27, 2025.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0 for all Reporting Persons
	(ii) Shared power to vote or to direct the vote: AAIA 1,920,000 AISG 1,920,000 AISG GP 1,920,000 Apollo Life 1,920,000 Apollo Life GP 1,920,000 Capital Management 1,920,000 Capital Management GP 1,920,000 Management Holdings 1,920,000 Management Holdings GP 1,920,000
	(iii) Sole power to dispose or to direct the disposition of: 0 for all Reporting Persons
	(iv) Shared power to dispose or to direct the disposition of: AAIA 1,920,000 AISG 1,920,000 AISG GP 1,920,000 Apollo Life 1,920,000 Apollo Life GP 1,920,000 Capital Management 1,920,000 Capital Management GP 1,920,000 Management Holdings 1,920,000 Management Holdings GP 1,920,000
Item 5.	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.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See response to Item 2(a), which is incorporated by reference herein.
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.

Apollo Management Holdings GP, LLC

Signature:	/s/ William B. Kuesel
Name/Title:	William B. Kuesel, Vice President
Date:	08/14/2025

Athene Annuity and Life Company

Signature:	Apollo Insurance Solutions Group LP
Name/Title:	Investment Adviser
Date:	08/14/2025

Signature:	AISG GP Ltd.
Name/Title:	General Partner
Date:	08/14/2025

Signature:	/s/ Angelo Lombardo
Name/Title:	Angelo Lombardo, Authorized Signatory
Date:	08/14/2025

Apollo Insurance Solutions Group LP

Signature:	AISG GP Ltd.
Name/Title:	General Partner
Date:	08/14/2025

Signature:	/s/ Angelo Lombardo
Name/Title:	Angelo Lombardo, Authorized Signatory
Date:	08/14/2025

AISG GP Ltd.

Signature:	/s/ Angelo Lombardo
Name/Title:	Angelo Lombardo, Authorized Signatory
Date:	08/14/2025

Apollo Life Asset L.P.

Signature:	Apollo Life Asset GP, LLC
Name/Title:	General Partner
Date:	08/14/2025

Signature:	Apollo Capital Management, L.P.
Name/Title:	Managing Member
Date:	08/14/2025

Signature:	Apollo Capital Management GP, LLC
Name/Title:	General Partner
Date:	08/14/2025

Signature:	/s/ William Kuesel
Name/Title:	William B. Kuesel, Vice President
Date:	08/14/2025

Apollo Life Asset GP, LLC

Signature:	Apollo Capital Management, L.P.
Name/Title:	Managing Member
Date:	08/14/2025

Signature:	Apollo Capital Management GP, LLC
Name/Title:	General Partner
Date:	08/14/2025

Signature:	/s/ William B. Kuesel
Name/Title:	William B. Kuesel, Vice President
Date:	08/14/2025

Apollo Capital Management, L.P.

Signature:	Apollo Capital Management GP, LLC
Name/Title:	General Partner
Date:	08/14/2025

Signature:	/s/ William B. Kuesel
Name/Title:	William B. Kuesel, Vice President
Date:	08/14/2025

Apollo Capital Management GP, LLC

Signature:	/s/ William B. Kuesel
Name/Title:	William B. Kuesel, Vice President
Date:	08/14/2025

Apollo Management Holdings, L.P.

Signature:	Apollo Management Holdings GP, LLC
Name/Title:	General Partner
Date:	08/14/2025

Signature:	/s/ William B. Kuesel
Name/Title:	William B. Kuesel, Vice President
Date:	08/14/2025

FAQ

How many Series F MRPS does the Apollo/Athene group report owning in CSQ?

They report owning 1,920,000 Series F MRPS of Calamos Strategic Total Return Fund.

What percentage of the Series F class does the reported holding represent for CSQ?

The reported position represents 48.0% of the MRPS class based on 4,000,000 shares outstanding as of April 30, 2025.

Do any reporting persons claim sole voting or dispositive power over the shares in this CSQ filing?

No. All reporting persons report 0 sole voting power and 0 sole dispositive power, with shared power over 1,920,000 shares.

Was this filing presented as an attempt to influence control of Calamos Strategic Total Return Fund (CSQ)?

No. The certification states the securities were acquired and are held in the ordinary course of business and not to change or influence control of the issuer.

On what date and basis is the percent ownership calculated in this CSQ Schedule 13G/A?

The percent is based on 4,000,000 MRPS outstanding as of April 30, 2025, per the issuer's certified shareholder report filed June 27, 2025.