USPS Rule Clarifies Postmark

The United States Postal Service (USPS) issued a final rule effective December 24, 2025, that highlights that a postmark does not necessarily indicate the first day that the USPS had possession of the item, but rather it is often indicative of receipt at a first processing facility—which may be later than the date first accepted by USPS. The rule comes as the USPS embarks on a network modernization initiative featuring updated regionalized processing and distribution centers.

According to Internal Revenue Code Section 7502, when you mail a tax form, payment, or other document, the date shown on the USPS postmark is considered the date your item was received by the required entity, as long as you follow the rules. However, in light of the new way the USPS processes mail, the postmark date might actually be after the day you gave your item to the USPS. This means your document could be considered sent later than you expected, depending on when it gets processed and stamped.

As year-end contribution and reporting deadlines approach, those still using the USPS and relying on a postmark date as proof of timely contribution, delivery, or filing should be aware of these developments. The preamble notes that clarification is intended to educate customers so that they can adjust their mailing behavior (e.g., mail such items sooner). The guidance also indicates that alternatively, customers can obtain a manual local postmark at a retail location or purchase a Certificate of Mailing.