AUTOMATIC DATA PROCESSING INC

(a) On April 28, 2025, the Board of Directors (the "Board") of the Company amended and restated the Company's By-Laws to make minor clarifying changes under Sections 2.04 and 2.05 of the By-Laws. The full text of the amended and restated By-Laws is attached hereto as Exhibit 3.1 and is incorporated herein by reference.

(c)The following individuals became executive officers under Section 16 of the Securities Exchange Act of 1934 during the fiscal quarter ended March 31, 2025. We are reporting the following trading arrangements that are intended to satisfy the affirmative defense of Rule 10b5–1(c), which the executive officers adopted prior to becoming executive officers. For the fiscal quarter ended March 31, 2025, none of the Company’s directors or executive officers adopted orterminated any contract, instruction or written plan for the purchase or sale of Company securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any “non-Rule 10b5-1 trading arrangement.”

(1) Securities reported in this column reflect options, restricted stock units (“RSUs”), performance-based stock units (“PSUs”) and shares of common stock, as appropriate. In the case of RSUs, quantities included in this column reflect the full amount of RSUs as reported in an officer’s respective plan and do not reflect the impact of tax withholding which will not be determined until the RSUs vest. In the case of PSUs (which have a three-year performance period), quantities included in this column reflect the application of performance factors at target and the inclusion of accrued dividend equivalents through the date of adoption of the trading arrangement. The PSU amounts do not reflect the impact of tax withholding which will not be determined until the PSUs vest. In addition, securities reported in this column include securities subject to limit orders and such orders may not fill if limit order conditions are not met.