Form 8949: Sales and Other Dispositions of Capital Assets

Who Files Form 8949

Every taxpayer who sold or otherwise disposed of capital assets during the year: stocks, bonds, mutual funds, real estate (when not Section 121 excluded), cryptocurrency, NFTs, options, and most personal-use assets sold at a gain.

What Form 8949 Reports

Each transaction is listed individually with date acquired, date sold, sales proceeds, cost basis, and resulting gain or loss. Transactions are categorized short-term (held one year or less) or long-term (held more than one year) and as having basis reported, not reported, or not provided to the IRS. Beginning 2025, digital asset (cryptocurrency) transactions are reconciled with broker-issued Form 1099-DA.

Key Deadlines

• Filed with the annual Form 1040 by April 15 (or October 15 with extension)

Common Mistakes

• Not adjusting basis for wash sales: losses are disallowed and added to the replacement security basis
• Missing the cost basis reset for inherited assets (stepped-up basis to date-of-death FMV)
• Crypto cost-basis errors when transferring assets between exchanges or wallets
• Reporting NFT or DeFi transactions as ordinary income when capital gain treatment applies

Best Practices

• Use specific identification (specific lot ID, HIFO, or other) instead of FIFO when selling appreciated stock or crypto. The default is often FIFO and produces higher tax than necessary.
• For cryptocurrency, run a year-end aggregator import (CoinTracker, Koinly, ZenLedger) to catch missing transactions, transfers between wallets, and basis errors.
• Reconcile every 1099-B box A (basis reported) and box B (basis not reported) with your records. Brokers commonly miss basis on inherited assets, RSU shares, and crypto.
• For wash sales, the disallowed loss adds to the basis of the replacement security. Track this manually if the broker does not, especially when wash sales cross account types.
• Use Schedule D to summarize long-term and short-term totals. Many tax software packages allow direct CSV import for high-volume traders.

Source: Official Form 8949 information at IRS.gov