SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* ARCH CAPITAL GROUP LTD. (Last) (First) (Middle) 100 PITTS BAY ROAD WATERLOO HOUSE, GROUND FLOOR (Street) PEMBROKE D0 HM 08 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 08/24/2021	3. Issuer Name and Ticker or Trading Symbol CALAMOS STRATEGIC TOTAL RETURN FUND [ CSQ ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Series D Mandatory Redeemable Preferred Shares	280,000(1)	I	See footnote 1

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* ARCH CAPITAL GROUP LTD. (Last) (First) (Middle) 100 PITTS BAY ROAD WATERLOO HOUSE, GROUND FLOOR (Street) PEMBROKE D0 HM 08 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* ARCH REINSURANCE LTD. (Last) (First) (Middle) 100 PITTS BAY ROAD WATERLOO HOUSE, 1ST FLOOR (Street) PEMBROKE D0 HM 08 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The reported securities are owned directly by Arch Reinsurance Ltd., a wholly-owned subsidiary of Arch Capital Group Ltd.

	/s/ Francois Morin	10/29/2021
	/s/ Tim Peckett	10/29/2021
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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