1099-DA reconciliation is the process of matching every sale a broker reports on Form 1099-DA to the taxpayer's complete transaction history across exchanges, wallets and blockchains. It confirms that the broker's proceeds tie to the taxpayer's records, supplies the basis the broker did not report, and identifies activity the form never saw.
A Form 1099-DA describes one broker's view of one account. The taxpayer's tax position is built from every account and every wallet, and the two have to agree wherever they overlap. Reconciliation starts from the form and works outward: each reported sale is located in the taxpayer's own history, its proceeds are compared, its basis is sourced, and anything on the form that the history does not contain, or in the history that the form does not contain, is explained.
The overlap is smaller than it looks. The form reports sales; the history also holds deposits, withdrawals, income and every disposal that took place outside a broker. Staking rewards, a liquidity pool deposit, a swap on a decentralised exchange and an ETH to WETH wrap can each have tax consequences, and none of them appears on any Form 1099-DA. A reconciliation that stops at the form treats a partial record as a complete one.
First, tie the proceeds. Each 1099-DA line is matched to a sale in the exchange's own transaction export by asset, date and units. Differences are usually fee treatment, the fair market value the broker used for a crypto-to-crypto exchange, or a single order the export shows as several fills. Under Regulations section 1.6045-1 the broker's proceeds are net of allocated transaction costs, so the export's gross figure will not match until the fee is applied the same way.
Second, source the basis. For a covered digital asset the broker's basis is compared with the taxpayer's lot records and any difference is traced to lot ordering or fees. For a noncovered unit the form is blank and the basis comes from the purchase at another venue, the sending wallet's history or the income event that created the units. Every transfer into the broker account has to be matched to a withdrawal from somewhere else, so that the units keep their original basis and holding period rather than arriving as a new acquisition at zero cost.
Third, add what the form omits. Disposals in self-custody, income of every kind and transactions at brokers that issued no form are entered from the on-chain and exchange records. The result is a single Form 8949 in which every 1099-DA line appears in the box matching its basis-reporting status and every other disposal appears in the box for sales not reported on a form. The totals then carry to Schedule D. The reconciliation is finished when the form's proceeds are fully accounted for and nothing in the history is missing from the return, which is the standard the 1099-DA and Form 8949 relationship demands.
An exchange reports every conversion of USDC into US dollars as a sale, because USDC is a digital asset. The taxpayer's software treats USDC as cash and records those conversions as nothing at all. The Form 1099-DA carries $140,000 of proceeds that the return does not mention. The gain on those lines is close to zero, but the IRS sees $140,000 of unreported sales, and the mismatch has to be answered after the fact instead of reconciled before filing.
Read our 1099-DA accounting and cost basis reconciliation
CountDeFi reconciles Form 1099-DA to your complete exchange, wallet and on-chain history, including proceeds tie-outs, transfer matching and off-form DeFi activity. See pricing.
