Sec Form 3 Filing - DEUTSCHE BANK AG\ @ NUVEEN MUNICIPAL HIGH INCOME OPPORTUNITY FUND - 2021-04-19

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person DEUTSCHE BANK AG\ 2. Issuer Name and Ticker or Trading Symbol NUVEEN MUNICIPAL HIGH INCOME OPPORTUNITY FUND [ NMZ] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) TAUNUSANLAGE 12 D-60325 3. Date of Earliest Transaction (MM/DD/YY) 04/19/2021 (Street) FRANKFURT AM MAIN, 2M00000 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Adjustable Rate MuniFund Term Preferred Shares 1,700 ( 1 ) I ( 2 ) By Subsidiary ( 2 ) ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other DEUTSCHE BANK AG\ TAUNUSANLAGE 12 D-60325 FRANKFURT AM MAIN, 2M00000 X DB Municipal Holdings LLC 60 WALL STREET NEW YORK, NY10005 X Signatures DEUTSCHE BANK AG, By: /s/ Daniela Pondeva 04/28/2021 Signature of Reporting Person Date DEUTSCHE BANK AG, By: /s/ Michael Caro 04/28/2021 Signature of Reporting Person Date DB MUNICIPAL HOLDINGS LLC By: /s/ Svetlana Segal 04/28/2021 Signature of Reporting Person Date DB MUNICIPAL HOLDINGS LLC By: /s/ John Werba 04/28/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The 1,700 adjustable rate munifund term preferred shares ("Shares") reported as acquired in Table I represent Shares of Nuveen Municipal High Income Opportunity Fund (the "Issuer") beneficially owned by DB Municipal Holdings LLC ("DBMH"). The Shares were purchased by DBMH from the Issuer. The Shares were acquired for a purchase price of $100,000 per share. DBMH is a wholly owned subsidiary of Deutsche Bank AG ("DB AG"). ( 2 )This statement is jointly filed by DB AG and DBMH. DB AG holds an indirect interest in the securities listed in Table I (the "Securities") by virtue of its indirect ownership of its subsidiary DBMH. ( 3 )Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) of the US Securities Exchange Act of 1934 or any other purpose, (i) acting (or has agreed or is agreeing to act together with any other person) as a partnership, limited partnership, syndicate, or other group for the purpose of acquiring, holding or disposing of securities of the Issuer or otherwise with respect to the Issuer or any securities of the Issuer or (ii) a member of any group with respect to the Issuer or any securities of the Issuer.

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 4(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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