Company: NMZ
Filing Date: 2025-07-07
Form Type: N-CSRS
Source: 0001193125-25-156000
Chunk: 23

Company: NUVEEN MUNICIPAL HIGH INCOME OPPORTUNITY FUND
Filing Date: 2025-07-07
Form: N-CSRS
Chunk 23
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 4 |

| (c) | • Net Investment Income (Loss) ratios reflect income earned and expenses incurred on assets attributable to 
 preferred shares issued by the Fund, where applicable.                                                      |

| • The expense ratios reflect, among other things, all interest expenses and other costs related to preferred                                                                                                                                            
 shares (as described in Notes to Financial Statements) and/or the interest expense deemed to have been paid by the Fund on the floating rate certificates issued by the special purpose trusts for the self-deposited inverse floaters held by the Fund 
 (as described in Notes to Financial Statements), where applicable, as follows:                                                                                                                                                                          |

|            |     |          | Ratios of Interest 
 Expense to         
 Average Net Assets 
 Applicable         
 to Common Shares   |
|            |     |     NDMO |                    |
| 4/30/25(d) |     | 1.62%(e) |                    |
| 10/31/24   |     |     1.68 |                    |
| 10/31/23   |     |     1.54 |                    |
| 10/31/22   |     |     0.75 |                    |
| 10/31/21   |     |     0.33 |                    |
| 10/31/20   |     |     0.03 |                    |

| (d) | Unaudited. |

| (e) | Annualized. |

| (f) | Value rounded to zero. |

See Notes to Financial Statements 187

Financial Highlights (continued) The following table sets forth information regarding each Fund’s outstanding senior securities as of the end of each of the Fund’s last five fiscal periods, as applicable.

|            |     | AMTP Shares          |         |     |                   |         |     | MFP Shares           |          |     |                       |          |     | VRDP Shares          |            |     |                   |          |     |                           |
|            |     | Aggregate            
 Amount   Outstanding 
 (000)(a)             |         |     | Asset             
 Coverage Per      
 $100,000 Share(b) |         |     | Aggregate            
 Amount   Outstanding 
 (000)(a)             |          |     | Asset                 
 Coverage Per          
 $100,000 Share(b),(c) |          |     | Aggregate            
 Amount               
 Outstanding (000)(a) |            |     | Asset             
 Coverage Per