On December 24, 2025, the U.S. Postal Service (“USPS”) finalized a rule adding Section 608.11, “Postmarks and Postal Possession,” to the Domestic Mail Manual.
The rule clarifies that the date on an official USPS postmark reflects the moment the mail piece is first processed by an automated USPS sorting facility. It is not the moment the mail piece was dropped off or received by the USPS.
Why The Rule Matters for Health, Tax & Benefits Filings
Many federal and state deadlines, especially in tax and benefits contexts, rely on the postmark date as the legal filing date for mailed documents under statutes such as Internal Revenue Code Section 7502 (“timely mailing, timely filing”). If the postmark date is after the statutory deadline, regulators may treat the filing as late, even if the item was dropped off with USPS before the deadline.
This shift is consequential for:
- Tax returns, payments, extensions, and other IRS correspondence;
- Benefit claims and appeals where administrative deadlines often hinge on postmark evidence;
- Compliance and reporting filings that require mailed submissions by a specific date; and
- ERISA-required notices and communications.
A taxpayer can incur late filing penalties if a return is given a late postmark. In health care and other benefits administration, late appeals or missed deadlines can result in denied coverage, loss of benefits, loss of discretionary review, or regulatory penalties for late filings (e.g., COBRA notices).
GROOM INSIGHT: To preserve rights in time-sensitive filings, we recommend the following options:
• Presenting critical mail pieces at the USPS retail counter and requesting a manual postmark on the date of deposit;
• Using certified or registered mail or obtaining a certificate of mailing to provide additional proof of timely submission;
• Building in filing buffer time to account for potential processing delays;
• Electronic filing whenever possible; and/or
• Ensuring staff and compliance teams are fully educated on the practical implications of the updated postmark rule.
Taxpayers may also use IRS-designated private delivery services, such as DHL Express, FedEx, and UPS to preserve rights in time-sensitive filings. However, only specific service levels (e.g., overnight or next day) approved by the IRS qualify for timely mailing treatment.
Groom attorneys will continue to closely monitor USPS guidance and regulatory developments and are available to answer questions about the rule and its implications.
