The timing rule, and the one exception that makes year-end giving work. 26 CFR 1.170A-1(b) says a contribution is ordinarily made "at the time delivery is effected," and then supplies the practical rule people rely on: "The unconditional delivery or mailing of a check which subsequently clears in due course will constitute an effective contribution on the date of delivery or mailing." The same paragraph treats a properly endorsed stock certificate delivered or mailed to the charity as a completed gift on delivery or mailing, but if the certificate goes to your own bank or broker for transfer into the charity's name, the gift is completed only when the stock is transferred on the corporation's books. A pledge paid with securities in the last week of December can therefore land in either year depending on which route the shares take.
Enforceability is genuinely uncertain, and the government has said so. In Notice 2017-73, Treasury and the IRS recorded the difficulty directly: commenters noted "the difficulty inherent in determining whether a commitment identified as a 'pledge' is legally enforceable under state law or merely an indication of charitable intent," that enforceability "often turns on factual details," and Treasury and the IRS agreed "that it is difficult for sponsoring organizations to differentiate between a legally enforceable pledge by an individual to a third-party charity and a mere expression of charitable intent." That is a federal agency describing the state-law question as hard, which is a better guide for a donor than any confident general rule.
Somebody else paying your pledge is two transfers, not one. Notice 2017-73 cites Revenue Ruling 81-110 for the proposition that a payment by a third party to a charity explicitly made to pay a donor's legally enforceable pledge is treated as a gift from the third party to the donor, and then a charitable contribution from the donor to the organization. That is the mechanism behind the two rules below, and it is why "have the foundation pay it" is not a neutral administrative choice.
A private foundation generally cannot pay its founder's pledge. 26 CFR 53.4941(d)-2(f)(1) provides that "if a private foundation makes a grant or other payment which satisfies the legal obligation of a disqualified person, such grant or payment shall ordinarily constitute an act of self-dealing." There is a narrow grandfather for pledges enforceable under local law and made on or before April 16, 1973, which is of no use to anyone making a pledge now. The clean approach is for the individual to pledge in their own name and the foundation to make its own grants in its own name.
The donor-advised fund question has been open since 2017 and is still open. Section 4967 taxes a distribution that results in a more than incidental benefit to a donor or advisor. In Notice 2017-73 the Treasury Department and the IRS said they were "considering proposed regulations under section 4967" that would, if finalized, provide that a distribution from a fund to a charity is not a more than incidental benefit "merely because the Donor/Advisor has made a charitable pledge to the same charity (regardless of whether the charity treats the distribution as satisfying the pledge)," subject to three conditions: the sponsoring organization makes no reference to the pledge when making the distribution, no other more than incidental benefit reaches the donor, and the donor claims no section 170 deduction for the distribution. That regulation has never been issued: as of September 2026 no final regulation under section 4967 addresses charitable pledges, and every donor-advised-fund rulemaking the Internal Revenue Service has published since 2023 is a proposed rule under section 4966, a different provision. The position stated in the Notice therefore remains a description of what the agencies were considering rather than law. In practice the sponsoring organization's own policy is what governs whether it will make the grant at all, and sponsors' policies differ.
At death, an unpaid pledge is not simply a debt of the estate. 26 CFR 20.2053-5 provides that a pledge or subscription, "even though enforceable against the estate, is deductible ... only to the extent that" the liability was contracted for adequate and full consideration in cash or its equivalent, or "it would have constituted an allowable deduction under section 2055 ... if it had been a bequest." Most charitable pledges reach relief through the second route, as a charitable deduction rather than as a claim against the estate. The distinction matters where the pledged organization would not qualify under section 2055.
