March 2026
Background
Under Section 7502 of the Internal Revenue Code, if an item was properly deposited in the US Mail (adequate postage, properly addressed, etc.) on or before the due date, it was deemed to have been filed on the date it was mailed even if it was not received by the IRS until after the due date. This is commonly referred to as the “Mailbox Rule.” Timely filing by the sender was typically determined with reference to the postmark.
Recent Changes
The U.S. Postal Service (“USPS”) has announced new rules that may result in the postmark reflecting the date when the item reaches the USPS’s automated processing facility, rather than the date it was mailed at the post office. This change became effective December 24, 2025.
Some Practical Takeaways
In situations where you are filing a tax return or other document or making a payment to the IRS and need to rely on the Mailbox Rule to ensure timely filing, you should bring the item to the post office and request a manual postmark. Alternatively, you could send the item via certified mail, where your receipt will be hand stamped.
Although the Mailbox Rule is still in effect, some additional care is required to ensure that you will qualify.
If we can provide any additional information, please contact Bill Miller at wmiller@bizlawma.com.
This memorandum is intended to provide general information of potential interest to clients and others. It does not constitute legal advice. The receipt of this memorandum by any party who is not a current client of the Business Law Group does not create an attorney-client relationship between the recipient and the firm. Under certain circumstances, this memorandum may constitute advertising under the Rules of the Massachusetts Supreme Judicial Court and the bar associations of other states.