Stelter’s Senior Gift Planning Consultant, Lynn M. Gaumer, J.D., CAP®, explains how a new postmark and processing rule could affect year-end giving — and why fundraisers should start planning now to incorporate this change into their 2026 year-end messaging.
Late in December, during the holiday bustle, the U.S. Postal Service (USPS) quietly implemented a change that could affect year-end charitable giving—especially for donors who rely on mail.
Effective December 24, 2025, USPS clarified in its Domestic Mail Manual that most postmarks will now be applied when mail is first processed at regional processing centers rather than at the local post office or mailbox where the item was dropped.
Traditionally, donors could drop a check into a blue USPS mailbox—even on December 31—and count on the postmark date to reflect that send date for IRS deduction purposes. Under the new system, that same envelope might not reach a regional hub until several days later and could end up with a postmark dated in the new year—affecting whether the gift qualifies as deductible for the prior tax year.
To understand how dramatic this shift is, consider the scale of the change in processing infrastructure:
- About 60 Regional Processing and Distribution Centers (RPDCs) will serve as the major mail-sorting hubs across the country under the new USPS network model.
- These regional hubs replace or consolidate much of the work previously done at nearly 200 local processing centers.
- Meanwhile, there are over 30,000 local post office locations nationwide providing retail and delivery services—but most will no longer be where a sender’s mail gets its postmark under the new system.
So instead of your donor’s holiday check likely getting postmarked at their neighborhood post office, it may now receive its date stamp days later once it reaches one of a much smaller number of centralized mail-processing hubs. This difference in location and timing is why the new rule matters so much for year-end givers—especially those in rural areas.
For nonprofits and donors alike, this change matters because the IRS generally looks to the postmark date as proof of when a charitable contribution was “delivered” for gift-deduction purposes. If a check mailed in December ends up postmarked January 2, the IRS could consider it a 2026 gift—even if the donor wrote the check and dropped it in the mailbox on December 31.
What You Can Do (and What to Tell Your Donors) for Year-End Giving 2026
Here are practical steps you—and your donors—can take to avoid surprises:
Encourage Early Mailing
Ask donors to mail contributions well before year-end. Even a buffer of a few days can help prevent regional processing delays.
Use USPS In-Person Options
If mailing late in December, a donor should take one of these steps:
- Take gifts inside a post office and request a manual (hand-stamped) postmark.
- Purchase postage at the counter (a Postage Validation Imprint shows the mailing date).
- Use certified/registered mail or a certificate of mailing to document the send date.
Promote Electronic Giving Alternatives
Online gifts, ACH or wire transfers, and credit card gifts processed by 11:59 p.m. December 31 are generally considered made in that tax year without reliance on USPS postmarks.
Communicate Early
Plan messaging now for year-end communications. A note in your fall communications about this postal change could save donors frustration later.
This change represents a new standard in how mail is postmarked. For fundraisers, understanding the implications now allows you to guide donors and plan ahead for year-end communications.