I just got this from a 501(c)(3) to which I have contributed for years. No guarantees, warrantees, or representations, but practitioners, beware.
The USPS recently changed the definition of when a piece of mail is considered postmarked or “mailed.” In the past, it was sufficient to drop your letter in any mailbox, and it was considered “mailed” based on a postmark applied at pick-up. However, under the new USPS rule, only certain processing centers can apply postmarks. In some regions, this may mean a mailed item won’t receive a postmark for several days after being dropped off at the post office or placed in a mailbox.
In a deficiency case or any non-Boechler you’d better check where you can mail.
Taishoff Law 
Effective 12/24/25, it says in the Federal Register.
https://www.federalregister.gov/documents/2025/11/24/2025-20740/postmarks-and-postal-possession
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consider impact – possible(1) IRS mailbox rule IRC 7502 -(2) mail in ballot/ absentee ballot - deposited inside U.S. - (3) voting by mail for overseas U.S. citizens – such as with APO
Attached pdf’s are: USPS postmark at central location change 24 Dec 2025 -an email - plain language example of change and potential impact –
USPS Changes to Postmark Date System Taking Effect December 24, 2025 â Fed Register USPS Changes to Postmark Date System Taking Effect December 24, 2025 â Current Federal Tax Developments 2025-20740 postmarks and postal possession Fed Reg USPS 11 24 2025
USPS Changes to Postmark Date System Taking Effect December 24, 2025 December 08, 2025 by Ed Zollars, CPASummary of the Final Rule The United States Postal Service (USPS) has adopted a final rule (FR Doc. 2025-20740) adding Section 608.11, “Postmarks and Postal Possession,” to the Domestic Mail Manual (DMM). The rule formally defines postmarks and identifies the types of markings that qualify as such. Its primary purpose is to improve public understanding that while a postmark confirms the USPS possessed a mailpiece on the date inscribed, that date does not necessarily align with the date the USPS first accepted possession of the item. The rule clarifies that the USPS does not postmark all mail in the ordinary course of operations and that the absence of a postmark does not imply the USPS did not accept custody.
Impact on Postmarking Timing The rule clarifies that the date displayed on a machine-applied postmark represents the “date of the first automated processing operation” performed at a processing facility, rather than the date the mail was dropped off. – Potential Delays: Because most postmarks are applied at processing facilities, the date inscribed may be later than the date the mailpiece was first accepted by the USPS. This discrepancy is expected to become more common due to the implementation of the “Regional Transportation Optimization” (RTO) initiative and the adoption of “leg-based” service standards. – Operational Reality: The rule codifies the operational reality that postmarking operations often cross calendar days or occur after transportation from a retail unit, meaning the postmark date is not a “perfectly reliable indicator” of the date of mailing.
Ensuring a Postmark on the Date of Delivery To assure a postmark is applied on the same day a document is delivered to the USPS, individuals must utilize specific retail services. The final rule outlines the following methods: – Request a Manual Postmark: Customers may present a mailpiece at a retail counter and request a “manual (local) postmark”. This postmark is applied at the time of acceptance, so the date aligns with the date the USPS took possession. – Postage Validation Imprint (PVI): When a customer pays for postage at a retail counter, the PVI label applied by the employee also indicates the date of acceptance. – Certificates of Mailing: Customers may purchase a Certificate of Mailing, or use Registered or Certified Mail, to obtain a receipt that serves as evidence of the date the item was presented for mailing,.
The rule explicitly warns that customer-applied pre-printed labels (e.g., from Self-Service Kiosks, Click-N-Ship, or meters) only show when postage was printed, not when the USPS accepted the item.
This change in USPS processes will have a potentially significant impact on tax filings. IRC §7502 specifically relies upon the postmark date applied to an envelope to determine timely filing if the document is not physically delivered to the IRS office by the due date for such document. Specifically IRC §7502(a)(1) states:
Read More USPS Changes to Postmark Date System Taking Effect December 24, 2025 â C…Summary of the Final Rule The United States Postal Service (USPS) has adopted a final rule ( FR Doc. 2025-2074…
-  Neil Neil AJ Sullivan, CPA, TEP, USTCP   PO Box 652, Purchase NY 10577 Tel ++ 914-713-0503   Fax ++ 914-713-0506     email   neilsullivan@att.net Â
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Gentlemen, thank you for the confirmation. Given the stress laid on USPS postmarks by Tax Court in all the Section 7502 mailed-is-filed cases, this latest USPS change will cause a massive displacement.
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