Company: NMZ
Filing Date: 2025-07-07
Form Type: N-CSRS
Source: 0001193125-25-156000
Chunk: 54

Company: NUVEEN MUNICIPAL HIGH INCOME OPPORTUNITY FUND
Filing Date: 2025-07-07
Form: N-CSRS
Chunk 54
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 reported to shareholders in the next annual or semi-annual report.

|                           |     | NVG |   |     | NZF |   |     | NMZ |   |     | NMCO |   |     | NDMO |   |
| Common shares repurchased |     |     | 0 |     |     | 0 |     |     | 0 |     |      | 0 |     |      | 0 |

FINRA BrokerCheck:The Financial Industry Regulatory Authority (FINRA) provides information regarding the disciplinary history of FINRA member firms and associated investment professionals. This information as well as an investor brochure describing FINRA BrokerCheck is available to the public by calling the FINRA BrokerCheck Hotline number at (800) 289-9999or by visiting www.FINRA.org. 207

Glossary of Terms Used in this Report

(Unaudited)

Average Annual Total Return:This is a commonly used method to express an investment’s performance over a particular, usually multi-year time period. It expresses the return that would have been necessary each year to equal the investment’s actual cumulative performance (including change in NAV or offer price and reinvested dividends and capital gains distributions, if any) over the time period being considered.

Duration:Duration is a measure of the expected period over which a bond’s principal and interest will be paid, and consequently is a measure of the sensitivity of a bond’s or bond fund’s value to changes when market interest rates change. Generally, the longer a bond’s or fund’s duration, the more the price of the bond or fund will change as interest rates change.

Effective Leverage:Effective leverage is a fund’s effective economic leverage, and includes both regulatory leverage (see leverage) and the leverage effects of certain derivative investments in the fund’s portfolio. Currently, the leverage effects of Tender Option Bond (TOB) inverse floater holdings are included in effective leverage values, in addition to any regulatory leverage.

Industrial Development Revenue Bond (IDR):A unique type of revenue bond issued by a state or local government agency on behalf of a private sector company and intended to build or acquire factories or other heavy equipment and tools.

Inverse Floating Rate Securities:Inverse floating rate securities are the residual interest in a tender option bond (TOB) trust, sometimes referred to as “inverse floaters”, are created by depositing a municipal bond, typically with a fixed interest rate, into a special purpose trust. This trust, in turn, (a) issues floating rate