Appreciated Stock Donation: Tax Math Explained

Donate $100,000 of appreciated stock instead of selling it, and a top-bracket California donor keeps roughly $23,800 in capital gains tax that would otherwise leave the account — before the charitable deduction does any work at all. That single number, the tax on the embedded gain, is what separates a stock gift from a cash gift of identical size. Most coverage frames appreciated stock donation as a deduction play. The deduction is the smaller half of the math.

For 2026, the arithmetic shifted. The One Big Beautiful Bill Act (OBBBA), signed July 4, 2025, capped the value of itemized deductions at 35 cents per dollar for taxpayers in the top 37% bracket and imposed a 0.5%-of-AGI floor on charitable deductions. Both provisions took effect for tax years beginning after December 31, 2025, per Greenberg Traurig’s analysis of the enacted text. The capital gains side of the equation — the part that actually drives stock donation — did not change. That asymmetry is the story.

The numbers that matter

Five figures define whether a stock gift beats a cash gift, and by how much.

Why the embedded gain does the heavy lifting

Selling appreciated stock triggers tax on the gain. Donating it does not. That is the entire mechanism, and its value scales with how much the position has appreciated, not with the donor’s generosity.

Consider a $100,000 position with a $20,000 cost basis — an $80,000 embedded long-term gain. Sell it, and the gain faces the 20% top long-term capital gains rate plus the 3.8% net investment income tax (NIIT), a combined 23.8% federal rate for high earners, according to IRS 2026 brackets reported by Kiplinger and Tax Foundation. That’s $19,040 in federal tax on the gain alone. Net cost of charitable giving calculations that ignore this number understate the case for stock by roughly a fifth of the appreciated value.

Donate the shares directly instead, and the charity receives the full $100,000. The IRS lets the donor deduct fair market value (FMV) — the full $100,000, not the $20,000 basis — provided the stock was held longer than one year, per IRS Publication 526 (2025). No capital gains tax is ever paid on the $80,000 gain. Two benefits stack: the avoided gain tax and the FMV deduction.

The direct-stock path delivers $19,040 more to charity and $6,664 more in deduction value, for the same $100,000 out of the portfolio. A donor who sells first pays the gain tax and then donates a smaller pile of cash — a strictly worse outcome whenever the position carries a long-term gain. The wider the gap between FMV and basis, the larger the advantage. A position with almost no appreciation collapses the difference to near zero; a position that has multiplied several times over makes direct donation close to mandatory for a tax-aware giver.

What the 2026 rules changed — and what they didn’t

Two OBBBA provisions bite here. Neither touches the capital gains avoidance.

The 35% cap is the more discussed change. A top-bracket donor previously deducted at the 37% marginal rate; now the itemized deduction is worth 35 cents per dollar. The new rule limits the value of itemized deductions to 35 cents per dollar, rather than the 37 cents that’s normal for the top bracket. On a $100,000 stock gift, that trims the deduction’s value from $37,000 to $35,000 — a $2,000 reduction. Real, but small against the $19,040 the donor avoids on the embedded gain.

The 0.5% floor is subtler and easier to miss. Itemizers who make charitable contributions may only claim a tax deduction to the extent that their qualified contributions exceed 0.5% of their adjusted gross income. A household with $600,000 of AGI loses the deduction on the first $3,000 of giving. For someone making a single large stock gift, the floor is a rounding error against a six-figure contribution. For a donor who spreads modest gifts across years, it compounds — which is precisely why donor-advised fund fees and structure now factor into timing decisions more than they did before 2026. Bunching several years of gifts into one clears the floor once instead of repeatedly.

What OBBBA left alone: the FMV deduction for long-term appreciated property, the permanent 60% AGI ceiling for cash gifts, and the entire capital gains framework. The 30% AGI limit on appreciated stock donated to public charities also survived — a donor cannot deduct stock worth more than 30% of AGI in a single year, though the excess carries forward up to five years, per IRS Publication 526 (2025).

The Finluxy Giving Efficiency Rate

The Finluxy Giving Efficiency Rate measures net dollars reaching charitable purpose divided by gross net-of-tax dollars committed by the donor, expressed as a percentage. Higher means the donor’s true out-of-pocket cost buys more charitable impact. For appreciated stock, the rate runs higher than for cash because the donor never funds the capital gains tax — that money would have vanished to the IRS on a sale regardless.

Take the $100,000 stock gift with an $80,000 embedded gain. The charity receives $100,000. The donor’s net cost is the $100,000 of value surrendered, minus the $35,000 deduction benefit, minus the $19,040 of capital gains tax that would have been owed had the donor sold — that tax is a cost the donor escapes, so it belongs in the efficiency calculation as avoided outflow. Net economic cost: roughly $58,000. Impact delivered: $100,000. Rate: about 172%.

The lower a position’s cost basis, the higher the efficiency rate — a near-zero-basis position carries the maximum embedded gain and thus the maximum avoided tax. This inverts intuition. The stock a donor is most reluctant to sell, because the tax hit on sale would be brutal, is exactly the stock most efficient to donate. The tax the donor dreads becomes the tax the donor sidesteps.

The insight most coverage misses

Standard guidance treats the deduction as the reason to donate appreciated stock. Run the 2026 numbers and the deduction is worth $35,000 while the avoided capital gains tax is worth $19,040 — the deduction is larger in absolute terms, so the framing seems right. It isn’t, because the deduction is available on cash too. The marginal benefit of choosing stock over cash is entirely the $19,040. Everything else is identical between the two paths.

That reframing changes who should care. A donor giving away recently purchased shares with minimal gain captures almost no advantage from the stock route and might reasonably donate cash for simplicity. A donor sitting on a decades-old position — employer stock, an early index-fund lot, a founder’s shares — captures close to the full 23.8% of the appreciation. The decision to donate stock versus cash is not a giving decision. It is a portfolio decision about which specific lots carry the largest unrealized gains, and it should be made lot by lot, not account-wide. Households comparing DAF versus private foundation efficiency often optimize the vehicle while ignoring which shares fund it — the more consequential choice.

Practical context for $150k+ households

At $150,000 of income, a household may or may not clear the standard deduction — $16,100 single, $32,200 married filing jointly for 2026, per IRS Rev. Proc. 2025-32. Charitable giving only produces federal tax benefit to the extent total itemized deductions exceed that threshold, and the 0.5% floor now shaves the first slice of giving off the top. A $150,000 household would forfeit the deduction on the first $750 of gifts. For this tier, the stock-versus-cash calculus still favors stock whenever appreciation exists, but the itemization question comes first — bunching multiple years of stock gifts into one, often through a DAF, is frequently the only way to clear the standard deduction at all.

Higher up the range, at $600,000 to $1 million of AGI, the analysis flips toward routine use of appreciated stock. These households hold the concentrated, low-basis positions where the 23.8% avoidance is most valuable, and they’re the households the 35% cap and 0.5% floor were written to reach. The threshold worth internalizing: once a position’s embedded gain exceeds roughly a quarter of its value, donating the shares rather than selling and giving cash improves the outcome by more than the OBBBA changes cost. For a donor weighing a charitable remainder trust structure or an outright gift, the stock-funding question sits underneath both. The vehicle determines timing and control; the asset determines efficiency. A tax advisor earns their fee here by identifying which lots to give, not merely whether to give — the lot selection is where the real money moves, and it rewards households that treat giving as an extension of portfolio management rather than a separate act of conscience. Charitable giving strategies for affluent households converge on the same conclusion: give the shares, keep the cash, and let the embedded gain fund the charity tax-free.