CA FTB Advises Taxpayers on USPS Postmark Updates and Filing Deadlines

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Published December 24th, 2025

Detected March 17th, 2026

Summary

The California Franchise Tax Board (FTB) is alerting taxpayers to recent USPS updates affecting mail postmark dates. Effective December 24, 2025, machine postmarks may reflect processing dates, not drop-off dates, potentially causing late filings. Taxpayers are advised to e-file or request manual postmarks.

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What changed

The California Franchise Tax Board (FTB) has issued a notice to inform taxpayers and tax professionals about changes to United States Postal Service (USPS) mail processing procedures that could impact the timeliness of mailed tax filings. Effective December 24, 2025, USPS implemented a final rule (Section 608.11 of the Domestic Mail Manual) indicating that machine-applied postmarks will generally reflect the date mail is first processed at a regional facility, rather than the date it is deposited in a local mailbox or post office. This change means that postmarks may occur several days after mail is sent, potentially causing tax returns, payments, and other correspondence to be considered untimely by the FTB.

Regulated entities and taxpayers who file or pay by mail should be aware of this change. To ensure timely filing and avoid penalties, the FTB strongly encourages e-filing and e-payments. For those who must file by mail, the FTB recommends requesting a manual postmark at a USPS retail counter, obtaining proof of mailing, or using services like Certified Mail or Registered Mail. Taxpayers should also allow extra time for mail delivery and postmarking to align with statutory deadlines, such as the April 15 tax payment deadline, to avoid potential penalties and interest.

What to do next

Advise clients to e-file tax returns and payments whenever possible.
If filing by mail, instruct clients to request a manual postmark at a USPS retail counter.
Ensure clients allow additional time for mail delivery and postmarking to meet statutory deadlines.

Penalties

Potential penalties and interest for late filings or payments.

Source document (simplified)

For Immediate Release

January 20, 2026

CA FTB advises taxpayers on USPS postmark updates and filing deadlines

Sacramento – The California Franchise Tax Board (FTB) is alerting taxpayers and tax professionals to recent updates to the United States Postal Service (USPS) transportation procedures that may affect postmark dates on mailed tax returns, payments, and other time-sensitive correspondence.

Effective December 24, 2025, USPS implemented a final rule adding Section 608.11 to the Domestic Mail Manual, clarifying that machine-applied postmarks will generally reflect the date mail is first processed at a regional facility rather than the date an item is dropped off at a local post office or mailbox. Under this new system, the postmark date may occur days after a taxpayer deposited mail with USPS, potentially causing mailed filings to be untimely.

Per the USPS website:

“...[W]e have made adjustments to our transportation operations that will result in some mailpieces not arriving at our originating processing facilities on the same day that they are 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 by a letter carrier or dropped off at a retail location.

As before, a customer can ensure that a postmark is applied to his or her mailpiece, and that the date on the postmark matches the date of mailing, by visiting a Postal Service retail location and requesting a manual (local) postmark at the retail counter when tendering their mailpiece. Manual postmarks will be applied free of charge.”

“The recent USPS changes highlight the importance of knowing how your return will be postmarked when submitting it by mail,” said State Controller and FTB Chair Malia M. Cohen. “Under the new system, a mailed return may not be postmarked until it reaches a processing facility, which may be days after drop-off. To help taxpayers avoid late filings and penalties, I strongly encourage e-filing whenever possible, and recommend requesting a manual postmark at a USPS retail counter if filing by mail.”

To avoid a late tax return, tax payment, or other filings, FTB strongly encourages taxpayers to consider e-filing and making e-payments if possible. For those who must file or pay by mail, taxpayers can help ensure they file or pay on time by visiting a USPS retail counter and requesting a manual (local) postmark, obtaining a postage validation imprint, certificate of mailing, using Certified Mail or Registered Mail with documented proof of mailing date.

As a reminder: To avoid penalties, be sure to pay any taxes owed by April 15. Mailers should allow extra time for postmarking and delivery to avoid penalties, interest, or processing issues that could arise if postmarks do not align with statutory deadlines.

File and pay taxes online

For faster service, take advantage of FTB's 24/7 online self-service options.

To e-file your California tax return, visit CalFile, which allows most Californians to e-file their state tax return for free.

FTB offers several payment options. You can pay your taxes with your checking or savings account using Web Pay, by credit card (fees apply), or set up a payment plan if you qualify (fees apply).

For more information on filing options and important tax deadlines, visit ftb.ca.gov or consult your tax professional.

Last updated: 02/19/2026 The Franchise Tax Board administers two of California’s major tax programs: Personal Income Tax and the Corporation Tax. We also administer other non tax programs and delinquent debt collection functions, including delinquent vehicle registration debt collections on behalf of the Department of Motor Vehicles, and court–ordered debt. Annually, our tax programs collect more than 75 percent of the state’s general fund. For more information on other taxes and fees in California, visit: taxes.ca.gov.