An amount in Box 3 of Form 1099-DIV is a nondividend distribution, meaning it’s a return of your own invested capital rather than income. You don’t pay tax on it in the year you receive it. Instead, you subtract it from the cost basis of the shares that paid it, and that lower basis will produce a larger taxable gain (or smaller loss) whenever you sell.
What the Box 3 Amount Actually Is
Under the Internal Revenue Code, a payment from a corporation or fund counts as a “dividend” only to the extent it comes out of current or accumulated earnings and profits.1Office of the Law Revision Counsel. 26 USC 316 – Dividend Defined Anything paid beyond those earnings and profits is treated as your own capital being handed back to you. That excess is what lands in Box 3.
The payer does this math before the form is issued. The portion covered by earnings and profits goes in Box 1a as an ordinary dividend; the excess goes in Box 3 as a nondividend distribution.2Internal Revenue Service. Instructions for Form 1099-DIV You don’t need to recalculate anything to accept the split shown on your form.
Some investments generate Box 3 amounts year after year. Real estate investment trusts and master limited partnerships are the most common examples, because their cash payouts routinely exceed the earnings-and-profits figure that defines a dividend. If you hold either in a taxable account, expect Box 3 activity to be a regular feature of your 1099-DIV.
What You Do With It This Year
The immediate effect is a basis reduction, not a tax bill. Lower your adjusted cost basis in the shares dollar-for-dollar by the amount in Box 3.3Internal Revenue Service. Publication 550 – Nondividend Distributions
Say you bought 100 shares of a REIT at $50, for a $5,000 basis. Over three years, Box 3 amounts total $600. Your adjusted basis is now $4,400. Sell the shares later for $5,500 and your taxable gain is $1,100, not $500. The return of capital was never taxed as income, but it enlarged the eventual gain by the same amount.
If you bought your shares in separate lots at different prices and can’t identify which lot the distribution belongs to, reduce the basis of the earliest purchased shares first.3Internal Revenue Service. Publication 550 – Nondividend Distributions
When It Becomes Taxable
A nondividend distribution stays tax-free only while you still have basis to absorb it. Once your adjusted basis reaches zero, any further Box 3 amount is treated as a capital gain from a sale, taxed as long-term or short-term based on how long you’ve held the shares.4Internal Revenue Service. Topic No. 404, Dividends and Other Corporate Distributions
Federal law lays this out as a three-step ordering rule for any corporate distribution: the dividend portion is included in gross income, the nondividend portion reduces basis, and anything left over after basis hits zero is treated as gain from the sale of the stock.5Office of the Law Revision Counsel. 26 USC 301 – Distributions of Property
This is where long-time REIT and MLP holders sometimes get caught. After years of seemingly tax-free distributions eating away at basis, an investor can end up with taxable capital gains from distributions without having sold a single share. Watching your basis annually is what prevents that from becoming a surprise.
How to Report It on Your Return
In an ordinary year, a Box 3 amount doesn’t appear anywhere on Form 1040. You adjust your basis in your own records and move on. There’s no line on the 1040 or on Schedule D for a nontaxable return of capital.
The picture changes once basis is exhausted. Report any nondividend distribution received after basis reaches zero on Form 8949, using Part I for shares held one year or less and Part II for shares held more than one year, with totals carrying to Schedule D.6Internal Revenue Service. Mutual Funds (Costs, Distributions, Etc.)
When you eventually sell, your reduced basis is what produces the gain shown on the sale. Broker cost-basis reporting sometimes accounts for prior return-of-capital adjustments and sometimes doesn’t. Check the year-end basis your broker shows against your own running total, and use your records if the two disagree.
Box 3 vs. Box 2a
The most common mix-up on this form is treating Box 3 like Box 2a. They aren’t similar.
Box 2a reports capital gain distributions from regulated investment companies and REITs, which are the fund’s realized long-term gains being passed through to you.7Internal Revenue Service. Form 1099-DIV These are taxable in the year received, at long-term capital gains rates, and reported on Schedule D (or directly on Form 1040 in some cases).
Box 3, by contrast, is a return of capital. It reduces your basis and produces no current tax. Only after your basis has been fully absorbed does it start generating capital gains for reporting on Form 8949 and Schedule D.
Downstream Effects Worth Knowing
Net Investment Income Tax
The 3.8% net investment income tax applies to the lesser of your net investment income or the amount by which your modified adjusted gross income exceeds $200,000 (single), $250,000 (married filing jointly), or $125,000 (married filing separately).8Internal Revenue Service. Topic No. 559, Net Investment Income Tax Capital gains are part of net investment income, so once Box 3 amounts start showing up as gains, or once you sell shares with a reduced basis, those amounts feed into this calculation.9Internal Revenue Service. Instructions for Form 8960
A nondividend distribution itself doesn’t add to AGI in the year received. But the larger gain it eventually produces at sale can push you across the NIIT threshold in that later year.
Social Security Benefit Taxation
Retirees should watch the same delayed effect on the “combined income” formula that determines how much Social Security is taxable. While the Box 3 amount is not yet taxable, it doesn’t move that calculation. In the year those distributions turn into capital gains, or in the year you sell shares with a reduced basis, the resulting gain can push combined income above the thresholds where 50% or 85% of benefits become taxable.
Keep a Running Basis Record
The most useful habit for any investor with recurring Box 3 activity is a running basis worksheet. Each year, subtract the nondividend distribution from your adjusted basis and note the new figure. Track lots separately if you bought in multiple purchases.
Brokerages often adjust cost basis for return of capital automatically, but not always, and errors do occur. Your own records, backed by the 1099-DIV forms themselves, are what govern for tax purposes. Keeping them current also tells you exactly when basis is about to reach zero, so you’re not surprised by a capital gain in a year you didn’t sell anything.