Company: CIMO
Filing Date: 2025-06-13
Form Type: 8-K/A
Source: 0001193125-25-140306
Chunk: 1

Company: CHIMERA INVESTMENT CORP
Filing Date: 2025-06-13
Form: 8-K/A
Chunk 1
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 7.75% Series C Cumulative Fixed-to-Floating Rate Redeemable Preferred Stock |     | CIM PRC           |     | New York Stock Exchange                   |
| 8.00% Series D Cumulative Fixed-to-Floating Rate Redeemable Preferred Stock |     | CIM PRD           |     | New York Stock Exchange                   |
| 9.000% Senior Notes due 2029                                                |     | CIMN              |     | New York Stock Exchange                   |
| 9.250% Senior Notes due 2029                                                |     | CIMO              |     | New York Stock Exchange                   |

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2of the Securities Exchange Act of 1934 (§240.12b-2of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

#### Explanatory NoteThis Amendment No. 1 (this “Amendment”) amends the Current Report on Form8-Kof Chimera Investment Corporation (“Chimera”), filed with the Securities and Exchange Commission on June 12, 2025 (the “Original Current Report”), in which Chimera reported, among other events, the execution of the Stock Purchase Agreement (as defined therein). This Amendment is solely for the purpose of filing a copy of the Stock Purchase Agreement as Exhibit 2.1 herewith. The Original Current Report otherwise remains unchanged.Item 9.01.Financial Statements and Exhibits(d) ExhibitsExhibitNo.Description2.1Stock Purchase Agreement, dated June 11, 2025, by and among Chimera Investment Corporation and the Sellers and their Representatives, each as defined therein.104Cover Page Interactive Data File (embedded within the Inline XBRL document)
SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

| CHIMERA INVESTMENT CORPORATION 
 Date: June 13, 2025            |     | By: |     | /s/ Phillip J. Kardis II              |