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Comment déclarer les transactions cryptographiques sur le formulaire 8949 et l'annexe D

Un guide complet pour déclarer vos transactions en cryptomonnaies sur le formulaire 8949 de l'IRS et l'annexe D. Découvrez ce qu'il faut déclarer, la différence entre les gains à court terme et à long terme, ainsi que le fonctionnement de la correspondance avec l'IRS.

📖 6 min read

Vous avez effectué des dizaines de transactions, échanges et transferts de cryptomonnaies cette année. Voici maintenant la partie difficile : tout déclarer à l'IRS. De nombreux utilisateurs se sentent dépassés en essayant de déterminer où classer chaque transaction et comment catégoriser les gains ou pertes. L'IRS exige des formulaires spécifiques — le formulaire 8949 et l'annexe D — pour déclarer avec précision votre activité en cryptomonnaies. Cependant, les règles sont complexes et les instructions sont incomplètes. Ce guide vous explique ce que vous devez savoir pour remplir correctement votre déclaration et éviter des erreurs coûteuses.

What Is Form 8949?

Form 8949 is the IRS form used to report capital asset transactions, including cryptocurrency sales, exchanges, or disposals. You list each transaction—date acquired, date sold, proceeds, cost basis, and gain or loss. The IRS requires separate reporting for short-term and long-term transactions, which are distinguished by the holding period. The form feeds into Schedule D, which summarizes your total capital gains and losses for the year. Properly filling out Form 8949 is critical, as errors can trigger IRS audits or penalties.

Short-Term vs. Long-Term Gains

The IRS classifies your gains based on how long you held the asset. Short-term gains come from assets held one year or less. These are taxed at your ordinary income rate, which can be higher. Long-term gains are from assets held longer than one year and are taxed at lower capital gains rates. When reporting, you must separate transactions accordingly. For example, if you bought BTC on January 1 and sold it on December 15, it's short-term. If you bought it on December 1 of last year and sold it this year, it's long-term.

How IRS Matching Works

The IRS uses automated matching systems to compare what you report versus what exchanges report. Many exchanges send Form 1099-B, which includes details like proceeds and cost basis. If your reported transactions don’t match their records, the IRS may flag your return for review. Accurate reporting of each transaction’s date, cost basis, and proceeds helps prevent mismatches. Keep detailed records, especially for transfers, forks, or tokens with multiple cost basis methods, to ensure your data aligns with IRS expectations.

What Transactions Do You Need to Report?

You must report every taxable event involving crypto: sales, exchanges, swaps, and certain transfers that constitute disposals. For example, if you trade ETH for BTC, that’s a taxable event. If you send crypto from your wallet to a decentralized exchange and then back, each transfer alone might not be taxable, but trades or swaps are. Also, earning crypto through staking, airdrops, or rewards can create taxable income that must be reported. Keeping track of each event’s date, amount, and fair market value in USD is essential.

Concrete Example

Suppose you bought 1 BTC for $20,000 on January 10. On June 15, you traded it for 15 ETH when Bitcoin’s price was $30,000. Later, on December 1, you sold the ETH for $25,000. Your report would include: - A sale of BTC with a basis of $20,000 and proceeds of $30,000, resulting in a short-term gain of $10,000. - A sale of ETH with a basis (cost) derived from the trade value, and proceeds of $25,000, resulting in a short-term or long-term gain depending on holding period. Failure to report these correctly can cause IRS notices or audits.

Reporting Short-Term vs. Long-Term Gains

typeclassificationtax_ratenotes
Held <= 1 yearShort-termOrdinary incomeTypically taxed higher; report on Part I of Schedule D
Held > 1 yearLong-termCap gains (0%, 15%, or 20%)Lower rates; report on Part II of Schedule D

Scenario: Reporting a Crypto Sale

  1. Bought 2 ETH for $4,000 on March 1.
  2. Sold 2 ETH on July 10 for $6,000.
  3. Held for over 1 year? No, so short-term.
  4. Report: Sale of ETH with basis of $4,000 and proceeds of $6,000.
  5. Gain of $2,000 taxed as ordinary income.

💰 Tax Impact:

This transaction results in a $2,000 short-term gain, taxed at your regular income rate, requiring accurate reporting on Form 8949 and Schedule D.

Frequently Asked Questions

Do I need to report transfers between my wallets?

Generally, transfers between your wallets are not taxable if they are just moving assets. However, if a transfer triggers a sale or swap, that event must be reported. When in doubt, consult your CPA or track each transfer carefully.

What if my exchange didn't send a 1099-B?

You are responsible for reporting all taxable events regardless of what exchanges send. Use your transaction history to fill out Form 8949 accurately. Moonscape can help automate this process.

Related Reading

Assurez-vous que vos transactions cryptographiques sont déclarées avec précision grâce à Moonscape. Générez des formulaires conformes à l'IRS et évitez les pénalités — laissez-nous gérer les détails pour vous.

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