The Real Math of a Charitable Remainder Trust

Published 2026-07-07 · Optimist Tax Advisors

The pitch for a charitable remainder unitrust is usually a single chart: the trust line compounding above the taxable line. The chart is not wrong, but it hides the terms of the trade. A fair evaluation compares three quantities.

What you give up

The remainder. At least 10% of the contributed value, actuarially, must pass to charity, and in most realistic designs the charity's expected share is well above the floor. If your philanthropic intent is zero, this is a pure cost and the strategy has to clear it with deferral value alone. It sometimes does at long horizons and high returns. It often does not.

What you get

• Deferral. The full pre-tax proceeds compound. Against an outright sale at a 30% combined rate, the trust starts with a 43% larger base. Distributions are taxed as they come out, income first under the character ordering rules.
• A deduction. The present value of the remainder is deductible in the contribution year, subject to adjusted gross income limits with a five-year carryforward. On a 6% payout lifetime CRUT for a donor in his forties, the deduction is modest; on shorter terms and lower payouts it grows.
• Diversification at zero tax cost. Often the underrated benefit: a concentrated position becomes a portfolio inside the trust immediately.

The honest comparison

Project after-tax wealth to you (distributions reinvested, taxes paid) under the trust against the outright sale, at your actual state rates and a defensible return assumption, and show the charity's terminal value alongside. When we run this for clients, the trust wins the personal-wealth comparison in perhaps half of realistic fact patterns, mostly long horizons, high embedded gains, and high state taxes, and wins the combined family-plus-philanthropy comparison in nearly all of them. Which comparison matters is a values question, and it should be answered before the structure is chosen, not after.