What is Schedule D?
Schedule D summarizes your capital gains and losses from selling investments and other assets, split between short-term and long-term.
How it works
Individual sales are detailed on Form 8949, then totaled here. Long-term gains (assets held over a year) get preferential rates; short-term gains are taxed like ordinary income. Net losses can offset gains, and up to $3,000 of leftover loss can offset your other income.
A quick example
What people get wrong
Holding an investment just past the one-year mark can flip a gain from ordinary rates to long-term rates — sometimes a 10–17 point difference. The calendar matters as much as the price.