8a — Long-Term Totals From Form 8949, Box D Updated for tax year 2025

What this line means

The total long-term gains and losses from assets reported on Form 8949 with Box D checked — meaning your broker reported both the proceeds and cost basis to the IRS. These are assets you held for more than one year before selling. Long-term gains qualify for the lower capital gains tax rates of 0%, 15%, or 20%.

Does this apply to you?

• You sold stocks, ETFs, or mutual funds through a brokerage account and held them for more than one year
• You received a 1099-B from your broker showing long-term sales with basis reported to the IRS
• You sold cryptocurrency held for more than a year through an exchange that reported cost basis
• You sold shares of a REIT, mutual fund, or other investment held longer than one year

Easy to overlook

Mutual fund shares use average cost basis by default If you sold mutual fund shares, your broker likely used the average cost method for calculating basis. This is fine, but if you specifically identified shares (selling the highest-cost shares first to minimize gain), you needed to elect that method in writing with your broker before the sale. You cannot retroactively cherry-pick lots. ¹ [SOURCE: IRS Schedule D instructions — Line 8a]

Reinvested dividends increase your cost basis Every dividend that was automatically reinvested bought new shares. Those reinvested amounts are part of your cost basis. Filers who use only their original purchase price as basis and ignore reinvested dividends overstate their gain, sometimes by thousands of dollars on long-held funds. ² [SOURCE: CP2000 pattern — unreported long-term brokerage sales]

Watch out for this

Ignoring reinvested dividends when calculating basis. If you invested $10,000 in a mutual fund ten years ago and reinvested $5,000 in dividends, your basis is $15,000, not $10,000. Using the lower basis means reporting $5,000 more gain than you actually have — and paying tax on money you already paid tax on when the dividends were reinvested.

Related lines on your return

• Line 1a — Schedule D — Short-term totals from Form 8949 Box A (same concept, under one year)
• Line 15 — Schedule D — Net long-term capital gain or loss
• Line 12 — Schedule D — Capital gain distributions (long-term gains from mutual funds reported on 1099-DIV)