Company: CIO
Filing Date: 2025-07-31
Form Type: DEFA14A
Source: 0001193125-25-169837
Chunk: 4

Company: City Office REIT, Inc.
Filing Date: 2025-07-31
Form: DEFA14A
Chunk 4
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. Any forward-looking statement made by the Company in this Current Report speaks only as of the date of this Current Report. Factors or events that could cause the Company’s actual results to differ may emerge from time to time, and it is not possible for the Company to predict all of them. The Company does not guarantee that the assumptions underlying such forward-looking statements contained in this Current Report are free from errors. The Company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future developments or otherwise, except as may be required by applicable securities laws.

| Item 9.01 | Financial Statements and Exhibits. |

| Exhibit 
 Number  
 99.1    |     | Description                                                                  
 Press Release, dated July 31, 2025, issued by City Office REIT, Inc.         |
|:--------|:----|:-----------------------------------------------------------------------------|
| 104     |     | Cover Page Interactive Data File (embedded within the Inline XBRL Document). |

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

| Date: July 31, 2025 |     | By: |     | CITY OFFICE REIT, INC.                                   
 /s/ Anthony Maretic                                      |
|:--------------------|:----|:----|:----|:---------------------------------------------------------|
|                     |     |     |     | Name: Anthony Maretic                                    
 Title:  Chief Financial Officer, Secretary and Treasurer |

Exhibit 99.1 City Office REIT Reports Second Quarter 2025 Results VANCOUVER—July 31, 2025 —City Office REIT, Inc. (NYSE: CIO) (the “Company,” “City Office,” “we” or “our”) today announced its results for the quarter ended June 30, 2025. Second Quarter Highlights

| • |     | Rental and other revenues were $42.3 million. GAAP net loss attributable to common stockholders was 
 approximately $107.2 million, or ($2.66) per fully diluted share;                                   |

| • |     | Core FFO was approximately $11.8 million, or $0.28 per fully diluted share; |

| • |     | AFFO was approximately $3.0 million, or $0.07 per fully diluted share; |

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