USPS Processing Changes May Delay Postmarks
Late Filings Could Trigger Penalties
FTB Recommends E-Filing or Requesting Manual Postmarks
California tax officials are urging taxpayers to exercise caution when submitting tax returns and payments by mail this year, warning that recent changes in U.S. Postal Service processing procedures could result in delayed postmarks and potential penalties.
The California Franchise Tax Board (FTB) said recent rule changes implemented by the United States Postal Service (USPS) may cause postmark dates to differ from the actual date mail is dropped off, potentially making timely filings appear late.
According to the FTB, USPS began enforcing a revised regulation on December 24, 2025, under a newly added Section 608.11 of the Domestic Mail Manual. Under the updated policy, machine-applied postmarks are based on the date mail is first processed at a regional processing facility, rather than the date it is deposited at a local post office or mailbox.
As a result, tax returns or payments mailed on or near filing deadlines could receive postmarks several days later than the drop-off date. In such cases, filings may be considered untimely, exposing taxpayers to late-filing penalties, interest charges, or processing delays.
USPS acknowledged on its website that recent transportation adjustments may prevent some mail from reaching processing facilities on the same day it is mailed. “This means that the date on the postmarks applied at our processing facilities will not necessarily match the date on which the customer’s mailpiece was collected or dropped off,” the agency stated.
USPS noted, however, that taxpayers can ensure a same-day postmark by visiting a post office retail counter and requesting a manual (local) postmark, which is applied free of charge.
Malia Cohen, who serves as chair of the FTB, strongly encouraged taxpayers to file electronically whenever possible.
“To avoid delays and penalties, taxpayers should take advantage of e-filing options,” Cohen said. “If mailing a return is unavoidable, they should request a manual postmark at a USPS retail counter to ensure the postmark reflects the actual date of mailing.”
The FTB also reminded taxpayers that the tax payment deadline remains April 15, regardless of postmark processing changes, and advised mailers to allow extra time if choosing to submit returns by mail.
State officials emphasized that electronic filing and electronic payments remain the fastest and safest way to meet filing requirements and avoid complications caused by postal delays.
