Company: ADP
Filing Date: 2025-05-07
Form Type: 424B2
Source: 0001193125-25-114878
Chunk: 27

Company: AUTOMATIC DATA PROCESSING INC
Filing Date: 2025-05-07
Form: 424B2
Chunk 27
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 and your activities. This summary is based on the Internal Revenue Code of 1986, as amended to the date hereof (the “Code”), administrative pronouncements, judicial decisions and final, temporary and proposed Treasury Regulations, changes to any of which subsequent to the date of this prospectus supplement may affect the tax consequences described herein, possibly on a retroactive basis. This summary does not address any aspect of state, local or non-U.S.taxation, or any taxes other than income taxes. You should consult your tax adviser with regard to the application of the U.S. federal tax laws to your particular situation, as well as any tax consequences arising under the laws of any state, local or foreign taxing jurisdiction. Tax Consequences to U.S. Holders This section applies to you if you are a U.S. Holder. You are a U.S. Holder if you are a beneficial owner of a Note that is, for U.S. federal income tax purposes:

| • |     | a citizen or individual resident of the United States; |

| • |     | a corporation, or other entity taxable as a corporation, created or organized in or under the laws of the United 
 States, any state therein or the District of Columbia; or                                                        |

| • |     | an estate or trust the income of which is subject to U.S. federal income taxation regardless of its source. |

Certain Additional Payments There are circumstances in which we might be required to make payments on a Note that would increase the yield of the Note, as described under “Description of Notes—Change of Control Offer.” We intend to take the position that the possibility that any such payments will be made does not cause the Notes to be treated as contingent payment debt instruments under the applicable Treasury Regulations. Our position is not binding on S-21

the Internal Revenue Service (“IRS”). If the IRS takes a contrary position, you may be required to accrue interest income based upon a “comparable yield” (as defined in the Treasury Regulations) determined at the time of issuance of the Notes (which is not expected to differ significantly from the actual yield on the Notes), with adjustments to such accruals when any contingent payments are made that differ from the payments based on the comparable yield. In addition, any income on the sale, exchange, retirement or other taxable disposition of the Notes would be treated as interest income rather than as capital gain. You should consult your tax adviser regarding the tax consequences if the Notes were treated as contingent payment debt instruments. The remainder of this discussion