USPS Postmark Changes May Affect Louisiana Tax Filings

revenue.louisiana.gov

Published February 5th, 2026

Detected March 17th, 2026

Summary

The Louisiana Department of Revenue is alerting taxpayers to changes in USPS postmark processing that may cause mailed tax documents to be postmarked later than the date they were mailed. This could result in penalties and interest for late filings, even if mailed on time. Taxpayers are encouraged to file and pay electronically via LaTAP.

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What changed

The Louisiana Department of Revenue (LDR) has issued a notice regarding changes in how the U.S. Postal Service (USPS) applies postmarks. USPS now generally postmarks mail based on the date of first processing, not the date of mailing. This change means that tax returns and payments mailed close to their due dates may receive a postmark after the due date, potentially subjecting taxpayers to penalties and interest under Louisiana law, which deems mailed items timely only if postmarked on or before the due date.

To mitigate these risks, the LDR strongly recommends that taxpayers utilize their electronic filing and payment portal, LaTAP, for immediate and secure submissions. For those who must mail documents, the LDR advises mailing early or requesting a manual postmark at a USPS retail counter, or using certified or registered mail if the deadline is imminent. Failure to ensure timely postmarks could lead to financial penalties and interest charges.

What to do next

Advise taxpayers of USPS postmark changes and potential impact on timely filings.
Encourage electronic filing and payment via LaTAP to avoid postmark issues.
Recommend mailing early or using USPS retail counter for manual postmarks for mailed submissions.

Penalties

Penalties and interest may be assessed if mailed tax returns and payments are postmarked after the due date due to USPS processing delays.

Source document (simplified)

USPS Postmark Changes May Affect Timely Tax Filings and Payments

Updated February 05, 2026

BATON ROUGE – The Louisiana Department of Revenue (LDR) is advising taxpayers of a change in how the U.S. Postal Service (USPS) applies postmarks to mailed items. This change may affect whether certain mailed tax returns and payments are considered timely.

USPS now generally applies postmarks based on the date an item is first processed at a postal facility, rather than the date it is placed in a mailbox or handed to a mail carrier. As a result, a mailed document may receive a postmark one or more days after it was actually mailed.

For tax returns and payments that are permitted to be submitted by mail, Louisiana law generally considers them timely only if the USPS postmark date is on or before the due date. Because postmark dates may occur after the actual mailing date, taxpayers who mail close to a deadline may be subject to penalties and interest, even if the item was mailed on time.

LDR Recommendation

To avoid issues related to USPS postmark timing, LDR strongly encourages taxpayers to file returns and make payments electronically using LaTAP.

LaTAP (Louisiana Taxpayer Access Point) is LDR’s secure, free online filing and payment portal. Electronic submissions are recorded immediately and are not affected by mail delays or postmark timing.

Access LaTAP at:
https://latap.revenue.louisiana.gov/

Taxpayers who choose to mail returns or payments are encouraged to mail early and, if close to a deadline, visit a USPS retail counter to request a manual postmark or use certified or registered mail.

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Byron Henderson
Public Information Director
[email protected]

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