Investment income, 1099 forms, and capital gains
Updated: 2026
Interest, dividends, and investment sales can arrive on several tax forms. Keep those forms together with cost-basis and transaction records so the return can be reviewed consistently.
Common investment tax forms
Form 1099-INT commonly reports interest, Form 1099-DIV reports dividends and certain distributions, and Form 1099-B often reports proceeds from sales of securities.
Keep all pages of consolidated brokerage statements. Supplemental pages can contain basis, acquisition dates, adjustments, or transaction details that are not obvious from the first page.
Basis and holding period matter
A capital gain or loss depends on more than sale proceeds. Adjusted basis and transaction details are needed to determine the result. Keep purchase records, reinvested-dividend information, and other basis documentation when available.
The holding period also matters. Property held for more than one year is generally treated as long-term for capital-gain purposes, while shorter holding periods are generally short-term.
Form 8949 and Schedule D
Most sales and other capital transactions are reported or reconciled on Form 8949 and then summarized on Schedule D when those forms apply. Brokerage reporting does not eliminate the need to review basis and adjustments.
If a brokerage statement shows missing basis, transferred assets, wash-sale adjustments, or transactions from more than one broker, gather the supporting records before return preparation.
Planning for a large gain
A large taxable capital gain can affect the amount due and may create an estimated-tax issue. If a major sale occurred during the year, reviewing the available records before filing season can help identify missing information.
What to prepare
A list of documents and supporting records for credits, dependents, mileage, expenses, and foreign items.