USPS postmark changes could affect employee benefit plans
Employee benefit plan sponsors and administrators should be aware of changes to the United States Post Office (USPS) postmark process that could affect when government filings and participant disclosures are considered to have been sent on time. Generally, documents sent by mail are considered timely if they are postmarked on or before the applicable due date. In the past, mail dropped off at the post office or put in a public mailbox before the final pickup time would be postmarked that same day. Under the new process, a same-day postmark is no longer certain.
Postmarks are generally applied by machine at USPS originating processing facilities. However, the USPS recently announced that changes to its transportation operations could result in mail being postmarked at an originating processing facility on a later date than it is dropped off at a local post office or received by a mail carrier. To avoid this potential delay and ensure the postmark reflects the date of mailing, plan sponsors and administrators using US mail can visit a USPS retail location and request a manual postmark at the counter (free of charge). Additionally, purchasing a certificate of mailing or using certified or registered mail services provides proof of timely mailing.
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Government filingsMany employee benefit plan filings to the government are now filed electronically, on a mandatory or voluntary basis — including (for example) the Form 5500, Annual Return/Report of Employee Benefit Plan, the Affordable Care Act (ACA)-related IRS Forms 1094-B, 1095-B, 1094-C, and 1095-C filed through the ACA information returns (AIR) system, and most filings to the Pension Benefit Guaranty Corp. (PBGC). However, exceptions may apply that allow these filings to be submitted by paper in certain cases. In addition, IRS still requires some submissions to be filed on paper via US mail or private delivery, including Form 5310-A, Notice of Plan Merger or Consolidation, Spinoff, or Transfer of Plan Assets or Liabilities; Notice of Qualified Separate Lines of Business.
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Participant disclosuresEmployee benefit plan disclosures to participants generally may be delivered electronically under IRS and DOL rules. However, many disclosures are still delivered by mail, especially to participants no longer actively employed by the plan sponsor and other participants who have affirmatively opted out of electronic delivery. These disclosures include a host of participant communications from defined benefit, defined contribution, and health and benefit plans, such as summary plan descriptions, enrollment notices, required annual disclosures, benefit claims and appeals notices and determinations, and COBRA notices. Getting participant disclosures manually postmarked is likely infeasible for companies with more than a handful of employees, so plan administrators or their vendors may now need to build a few extra days into their delivery timeline to account for the potential postmark delay.
Related resources
Non-Mercer resources
- Postmarking myths and facts (USPS)
- Overview of Domestic Mail Manual Section 608.11.0 “Postmarks and Postal Possession” (USPS, January 14, 2026)
- Final rule, Postmarks and Postal Possession (Federal Register, November 24, 2025)