Company: SFNC
Filing Date: 2025-09-10
Form Type: 424B5
Source: 0001193125-25-200113
Chunk: 53

Company: SIMMONS FIRST NATIONAL CORP
Filing Date: 2025-09-10
Form: 424B5
Chunk 53
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 under the Notes other than an event of default due to our failure to pay the principal of or interest on the Notes when due, upon:

| • |     | the satisfaction of the conditions described in “- Legal Defeasance,” other than with respect 
 to the sixth bullet point;                                                                    |

| • |     | our delivery to the Trustee of an opinion of counsel to the effect that the holders of the Notes will not                                                                                                                                             
 recognize income, gain or loss for United States federal income tax purposes as a result of such covenant defeasance and will be subject to United States federal income tax on the same amount and in the same manner and at the same times as would 
 have been the case if such covenant defeasance had not occurred; and                                                                                                                                                                                  |

| • |     | our delivery to the Trustee of an officer’s certificate and an opinion of counsel, each stating that, all             
 conditions precedent and subsequent provided for in the Indenture relating to the defeasance have been complied with. |

If we exercise our option to omit compliance with certain provisions of the Indenture as described in the immediately preceding paragraph and the Notes are declared due and payable because of the occurrence of an event of default that remains applicable, the amount of money and/or non-callablegovernment securities on deposit with the Trustee may not be sufficient to pay amounts due on the Notes at the time of acceleration resulting from such event of default. In such event, we will remain liable for such payments. Satisfaction and Discharge We may discharge our obligations under the Indenture and the Notes (except for certain surviving rights of the Trustee and our obligations in connection therewith) if: (a) all outstanding Notes and all other outstanding notes issued under the Indenture (i) have been delivered for cancellation, or (ii) (1) have become due and payable, (2) are by their terms due and payable within one year, (3) are to be called for redemption within one year under arrangements satisfactory to the Trustee for the giving of notice and redemption by the Trustee, (and in the case of clauses (1) and (3), we have irrevocably deposited or caused to be deposited with the Trustee an amount sufficient to pay and discharge the principal of (and premium, if any) and interest on all outstanding Notes and any other sums due on the stated maturity date or redemption date, as the case may be); (b) we have paid all other sums payable by us