Company: PAYX
Filing Date: 2025-04-09
Form Type: 424B2
Source: 0001193125-25-076822
Chunk: 1

Company: PAYCHEX INC
Filing Date: 2025-04-09
Form: 424B2
Chunk 1
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 or prior to the later of (x) October 7, 2025 or (y) the date that is five business days after any later date to which the parties to the Merger Agreement (as defined herein) may agree to extend the “End Date” in the Merger Agreement, (ii) the Merger Agreement is terminated or (iii) we notify the Trustee (as defined herein), in writing, that we will not pursue the consummation of the Acquisition, we will be required to redeem the notes of each series then outstanding at a redemption price equal to 101% of the aggregate principal amount of such series of notes, plus accrued and unpaid interest, if any, to, but excluding, the Special Mandatory Redemption Date (as defined herein). See “Description of Notes—Special Mandatory Redemption” in this prospectus supplement. The notes will be our senior unsecured obligations and will rank equally in right of payment with all of our other senior unsecured obligations from time to time outstanding. The notes will be issued only in registered book-entry form and in denominations of $2,000 and integral multiples of $1,000 thereafter. The notes will not be listed on any securities exchange. Currently, there is no public market for any series of the notes. Investing in the notes involves certain risks. See “ Risk Factors” beginning on page S-6of this prospectus supplement and in the documents incorporated by reference herein for a discussion of certain risks that you should consider in connection with an investment in the notes. Neither the Securities and Exchange Commission nor any state or other securities commission has approved or disapproved of these securities or determined if this prospectus supplement and the accompanying prospectus are truthful or complete. Any representation to the contrary is a criminal offense.

|                       |     | Public Offering Price(1) 
 Per Note                 |         |     | Total |               |     | Underwriting Discount 
 Per Note              |        |     | Total |            |     | Proceeds, Before Expenses, to Us 
 Per Note                         |         |     | Total |               |
|:----------------------|:----|:-------------------------|:--------|:----|:------|--------------:|:----|:----------------------|:-------|:----|:------|-----------:|:----|:---------------------------------|:--------|:----|:------|--------------:|
| 5.100% Notes due 2030 |     |                          | 99.720% |     | $     |