Company: MFAN
Filing Date: 2025-08-15
Form Type: 424B5
Source: 0001104659-25-079255
Chunk: 1

Company: MFA FINANCIAL, INC.
Filing Date: 2025-08-15
Form: 424B5
Chunk 1
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 as principal for its own account at a price agreed upon at the time of sale. If we sell common stock to a sales agent as principal, we will enter into a separate terms agreement with that sales agent, and we will describe this agreement in a separate prospectus supplement or pricing supplement. Our common stock is subject to certain restrictions on ownership designed to preserve our qualification as a real estate investment trust for federal income tax purposes. See “Description of Common Stock and Preferred Stock — Restrictions on Ownership and Transfer” in the accompanying prospectus. Investing in our common stock involves certain risks. Before buying any shares, you should read the discussion of material risks of investing in our common stock under the caption “Risk Factors” beginning on page S-6of this prospectus supplement and beginning on page 8 of our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, which is incorporated by reference into this prospectus supplement and the accompanying prospectus. Neither the Securities and Exchange Commission, or SEC, nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

| ​ | Goldman Sachs & Co. LLC | ​ | ​ | Barclays | ​ | ​ | BTIG | ​ |

| ​ | Citizens Capital Markets | ​ | ​ | Deutsche Bank Securities | ​ | ​ | Janney Montgomery Scott | ​ |

| ​ | JonesTrading | ​ | ​ | Keefe, Bruyette & Woods 
 A Stifel Company​       | ​ | ​ | Morgan Stanley | ​ |

| ​ | UBS Investment Bank | ​ | ​ | Wells Fargo Securities | ​ |

The date of this prospectus supplement is August 15, 2025

TABLE OF CONTENTS

TABLE OF CONTENTS PROSPECTUS SUPPLEMENT

| ​ | ABOUT THIS PROSPECTUS SUPPLEMENT                | ​ | ​ | ​ | ​ | S-1  | ​ | ​ |
| ​ | FORWARD-LOOKING STATEMENTS                      | ​ | ​ | ​ | ​ | S-2  | ​ | ​ |
| ​ | SUMMARY                                         | ​ | ​ | ​ | ​ | S-4  | ​ | ​ |
| ​ | OUR COMPANY                                     | ​ | ​ | ​ | ​ | S-4  | ​ | ​ |
| ​ | THE OFFERING                                    | ​ | ​ | ​ | ​ | S-5  | ​ |