‍This article was written by Justin Zanardi, CPA, a specialist in crypto tax and product lead at Summ. Justin breaks down why your 1099-DA cost basis may be missing and how to fix it, cleanly and practically.

You’ve probably heard the term “1099-DA” thrown around recently. You may have already received one. So what is it? And more importantly, what are you actually supposed to do with it? For those who want the detail, let’s dive in.

‍Definition: What the 1099-DA is (and isn’t)

A Form 1099-DA is an informational tax form issued by US digital asset brokers to report taxable digital asset disposals to both the taxpayer and the IRS.

It does not determine tax owed and does not replace the taxpayer’s obligation to report capital gains and losses on Form 8949 and Schedule D.

The 1099-DA is the start of the conversation, not the way you file your crypto taxes. Relying on this form alone without reconciling cost basis is how people accidentally overpay thousands in tax.

How the 1099-DA works in practice

Timing & rollout:

• The 1099-DA is effective for the 2025 tax year. Millions of US taxpayers will see this form for the first time this filing season.
• Because this is a brand-new reporting regime, the IRS designed a multi-year rollout of requirements.
• For 2025, brokers are only required to report gross proceeds.
• Starting in 2026, cost basis reporting begins, but only for qualifying covered assets.

Who reports what:

• A 1099-DA is issued by each digital asset broker (i.e., US-serving centralized exchanges).
• If you traded on Coinbase, Kraken, and Gemini, expect three separate consolidated 1099s.
• The IRS receives one 1099-DA per disposal transaction. Yes, you read that right, per transaction.
• Taxpayers usually receive a single consolidated PDF per exchange.

What's included (and not included) on the 1099-DA

The 1099-DA does not cover all your taxable crypto activity.

Transactions typically included:

• Crypto → fiat sales
• Crypto → crypto trades (with exceptions)

These transactions will show the asset sold, the number of units, gross proceeds, cost basis (often missing or incorrect), date acquired, date disposed, and gain/loss.

Transactions typically not included:

• Transfers off the exchange
• Certain NFT sales under $600 (subject to reporting thresholds)
• Certain stablecoin sales under $10,000 (subject to reporting thresholds)
• Wrapping / unwrapping
• Most staking and unstaking
• Lending transactions
• Rewards, interest, staking income (usually on 1099-MISC)
• All on-chain activity (DEX trades, DeFi, etc.)

Important note: Just because something doesn’t appear on the 1099-DA does not mean it’s non-taxable. You are still required to report all taxable disposals on your own 8949 as you have in prior years.

The Cost Basis Trap (this is where people get burned)

The trap

Unprepared tax payers will get burned here.

If you’re used to handing your 1099s to TurboTax or a preparer, doing that with the 1099-DA will often result in a massive overstatement of gains and tax paid.

Why this happens

For the 2025 tax year:

• No cost basis is reported to the IRS
• Many taxpayer copies will show $0 or “unknown” basis
• Some may show partial or incorrect basis

If cost basis isn’t corrected, the IRS assumes: 100% of proceeds = taxable gain

That’s how people end up overpaying thousands in tax on money they never actually made.

How to avoid the Cost Basis Trap

You must calculate and report your own cost basis.

You can do this:

• Manually, by reconstructing trades and filling out Form 8949 yourself, or
• By using crypto tax software that aggregates all wallets and exchanges and generates the 8949 with actual cost basis

Say you use Summ or another crypto tax tool. At a high level, the process looks like this:

1. Import each exchange’s 1099-DA
2. Add all other wallets and exchanges (this is important to track basis as it moves between platforms)
3. Let the software reconcile lots and populate the correct gain/loss on the 8949. No missing cost basis, no overpayment of gains.

This ensures:

• You’re not taxed on 100% of proceeds
• DeFi and other non-1099 activity is still reported (so you don’t accidentally underreport)
• Your totals actually tie out logically

Common mistakes taxpayers make with the 1099-DA

• Treating the 1099-DA as a completed tax report
• Importing the form without correcting cost basis
• Assuming missing basis equals taxable gain
• Failing to report non-1099 activity (DeFi, wallets, DEXs)
• Attempting to “match” the 1099-DA instead of reporting accurately (proceeds should match, but the cost basis is generally wrong or missing)

So what’s the point of the 1099-DA?

For years, the IRS had very limited visibility into crypto activity. Stocks had 1099-Bs. Crypto had nothing.

The 1099-DA changes that.

Even though it’s imperfect (especially early on), it gives the IRS:

• Confirmation that taxable disposals occurred
• A starting point to identify underreporting and non-filing

Going forward, the IRS will absolutely use this form to flag discrepancies. Ignoring it, or assuming it “handles reporting for you”, is a very bad idea. As mentioned before, the 1099-DA is the start of the conversation, not the way you file your crypto taxes.

Bottom Line

The 1099-DA is a visibility tool for the IRS, not a completed tax report for you. If you treat it as authoritative without reconciling cost basis, you’re likely to overstate gains.

In practice, that means taxpayers need some way to reconcile exchange-reported proceeds with their actual cost basis across wallets, exchanges, and on-chain activity, whether that’s done manually or with crypto tax software built to handle it correctly. Ignoring the form or assuming it “handles reporting for you” is where people get into trouble.

TL;DR

• The 1099-DA is the start of the conversation, not the way you file your crypto taxes
• It’s an informational form, not a tax return
• It does not replace Form 8949 and your obligation to report
• Missing cost basis = accidental overpayment (you should avoid this by manually adding to your 8949 or using a crypto tax software)
• You are allowed (and expected) to report your own basis

About Summ

Summ (formerly Crypto Tax Calculator) generates defendable crypto tax reports built on validated data. Summ’s reconciliation engine tracks transactions across 3,500+ exchanges, wallets, and blockchains, with deep on-chain coverage across DeFi, DEXs, NFTs, and complex protocols. By reconciling activity across sources, Summ produces clear, explainable tax reports that stand up when it matters.