Company: SFNC
Filing Date: 2025-07-23
Form Type: 424B5
Source: 0001193125-25-162761
Chunk: 28

Company: SIMMONS FIRST NATIONAL CORP
Filing Date: 2025-07-23
Form: 424B5
Chunk 28
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 effect. Any such change or differing interpretation could result in U.S. federal income tax consequences that differ from those summarized below. We have not sought any ruling from the Internal Revenue Service, or the IRS, with respect to any of the U.S. federal income tax consequences discussed below and there can be no assurance that the IRS would not assert, or that a court would not sustain, positions contrary to those described in this summary. This summary does not address all aspects of U.S. federal income taxation that may be relevant to particular investors in light of their individual circumstances, or to investors subject to special treatment under U.S. federal income tax laws, including, but not limited to, tax-exemptorganizations, insurance companies, banks or other financial institutions, partnerships or other entities classified as partnerships for U.S. federal income tax purposes, dealers in securities, persons liable for the alternative minimum tax, traders in securities that elect to use a mark-to-marketmethod of accounting for their securities holdings, persons who have acquired our common stock as compensation or otherwise in connection with the performance of services, persons subject to special tax accounting rules under Code Section 451(b), or persons that will hold our common stock as a position in a “hedging transaction,” “straddle,” “conversion transaction” or other risk reduction transaction. This summary does not address all aspects of U.S. federal income taxes, such as consequences under the Medicare contribution tax or the alternative minimum tax. Further, this summary does not address the consequences under any U.S. federal tax laws other than U.S. federal income tax laws, such as U.S. federal estate or gift tax laws, and does not address the consequences under the tax laws of any state, local, or non-U.S.jurisdiction. As used in this summary, the terms “non-U.S.holder” or “you” refer to a beneficial owner of our common stock that for U.S. federal income tax purposes is neither a partnership (including any entity or arrangement treated as a partnership for such purposes) nor a “United States person” which term refers to any person that, for U.S. federal income tax purposes, is or is treated as any of the following:

| • |     | an individual who is a citizen or resident of the United States (including certain former citizens and former 
 long-term residents of the United States);                                                                    |

| • |     | a corporation (or other entity or arrangement taxable for U.S. federal income tax purposes as a corporation)             
 created or organized in or under