Postmarks, rule changes, and remedies for clients’ 2025 charitable gifts

by SCF Team | February 17, 2026 | Siouxland Community Foundation Blog, Advisor Resources

USPS Postmark Changes and Year-End Charitable Deductions

If you were surprised to read about the ripple effect of a seemingly small change in U.S. Postal Service regulations late last year, you were not alone. For some donors, this shift may affect whether a charitable gift is deductible in 2025 or pushed into 2026. Here’s what you need to know, along with potential remedies for clients impacted by the change.

What’s the background with the IRS?

Under long-standing IRS guidance, a charitable contribution is generally considered “made” for tax purposes when the donor irrevocably parts with control of the gift. For gifts made by check and sent through the mail, the IRS has traditionally treated the date of the U.S. Postal Service postmark as the date of the gift, even if the charity receives the check later.

This approach is reflected in IRS Publication 526 and aligns with the broader “mailbox rule” under Internal Revenue Code Section 7502, which treats certain documents and payments as timely based on their postmark date rather than their date of receipt.

Okay, so if this is not an IRS issue, what happened?

In November 2025, the U.S. Postal Service (not the IRS) changed how postmarks are applied. Effective December 24, 2025, the official postmark date is now defined as the date of the first automated processing scan at a USPS processing facility, rather than the date a letter is dropped in a mailbox or handed to a clerk at a local post office.

This means mail deposited on December 31, 2025 may not receive a postmark until several days later, especially during the holiday surge. This change created widespread confusion and prompted the USPS to issue a “facts and myths” circular.

So what’s this got to do with the IRS?

Because the IRS still relies on the postmark to establish the date of a mailed charitable gift, this USPS change could cause a donation intended as a 2025 deduction to be treated as a 2026 contribution if the postmark reflects a January processing date.

If my client got caught up in this change, is the client totally out of luck for a 2025 charitable deduction?

Not necessarily. The underlying IRS rules for charitable contribution timing have not changed. Publication 526 still requires clients to “substantiate,” meaning document, the date of their gift. The IRS continues to rely on objective evidence to determine when the donor relinquished control.

What has changed is the ability to rely solely on an ordinary envelope postmark as proof of a year-end gift. Advisors should also understand that the statutory mailbox rule in Section 7502 is primarily directed at tax filings and payments to the IRS, but the IRS often uses similar concepts when evaluating charitable gift timing, particularly when a postmark is the primary evidence of mailing.

Okay, it sounds like all is not lost. What should I do to help my client?

If a client was impacted at the end of 2025, the first step is to gather and preserve any proof that establishes when the gift was actually mailed. Documentation such as a USPS Certificate of Mailing, certified or registered mail receipt, or a manually applied postmark or postage validation imprint obtained at the retail counter can help demonstrate that the donor relinquished control before year-end.

Even if the client has postal documentation, contemporaneous records such as copies of the check, client notes, and any correspondence with the charity should also be retained in case the deduction is questioned. In short, you may be able to build a defensible case supporting a 2025 deduction.

What should clients do for 2026 and beyond?

Advisors should help clients avoid this issue going forward. Electronic giving methods such as online donations, ACH or wire transfers, and completed transfers of publicly traded securities provide clearer and more immediate timestamps for deduction purposes. These methods also remove uncertainty tied to postal processing practices.

How can the Siouxland Community Foundation help?

Reach out to our team early in the year. Many clients rush around at year-end to complete charitable gifts, and this postal rule change is an excellent reason to plan ahead. Organizing charitable giving through a donor-advised fund at the Siouxland Community Foundation allows a client to make a donation for tax purposes well before year-end, secure the applicable deduction, and then recommend grants anytime to favorite charities.

As always, we look forward to serving you and your clients.