USPS rule change raises concerns for millions sending tax returns and ballots - what to know

USPS Mail Deadline: Over 160 million IRS tax returns move through the United States Postal Service every year. A new USPS postmark rule change now raises risks for taxpayers and voters. Since December 2025, the official postmark appears when mail reaches a regional sorting center, not when it enters a mailbox. The Internal Revenue Service uses postmarks to verify deadlines. Late processing could delay tax returns, mail-in ballots, and legal documents, experts warn.