If you trade crypto in Australia, assume the ATO already knows. The exchanges you use report your activity to it directly, so this has little to do with anyone watching your wallet.

That sounds worse than it is. Your exchange only sees part of the picture, and so does the ATO. Here is what it actually receives, where the gaps are, and what that means when you lodge your return.

What the data-matching program is

The ATO runs a crypto asset data-matching program that collects data from Australian crypto exchanges. It calls them "designated service providers." When you sign up to an exchange and complete identity checks, that exchange hands your details and your transaction records to the ATO.

This program has been going for a decade. It covers every financial year from 2014-15 through 2025-26, and the ATO estimates it captures data on 700,000 to 1.2 million individuals and entities every year.

The ATO then matches that data against what people report on their returns. Where the two line up, nothing happens. Where they don't, you can expect a prompt, and eventually a review. That is why some Australians have started receiving emails from the ATO about crypto. Those emails are the data-matching program in action.

What the ATO can see, and what it can't

People go wrong here in both directions. Some assume the ATO knows everything, others that it knows nothing, and both assumptions could cost you money.

What the ATO can see:

• Your identity, linked to the exchange accounts you have opened.
• The transactions on those exchanges, including buys, sells, and the AUD values reported by the exchange.

What the ATO generally cannot see:

• Your cost base. It may know you sold, but not what you originally paid, which is what your gain is actually calculated on.
• Your self-custody wallets and on-chain activity. Moving crypto to a private wallet, using DeFi protocols, or trading on decentralised platforms is not reported by an Australian exchange.
• Transfers between your own wallets and accounts, which are not disposals and should not be taxed as though they were.

So the gap matters. The ATO can see enough to know you have crypto activity, but not enough to work out your correct tax position. Report nothing and the mismatch is obvious. Report from memory and you could get the cost base wrong and overpay. Matching the form is easy. Being correct is harder. Your correct tax figure depends on the details the exchange never reported, like your cost base and your transfers. Working those out is the real task.

What this means for you

The activity the ATO is matching falls into a few buckets. Most people hit more than one.

Disposals (capital gains tax). Selling, swapping, gifting, or spending crypto all count as disposals, and each one triggers CGT. You report the net capital gain or loss in the CGT section of your return.

Income. Staking rewards and airdrops are ordinary income, taxed at their AUD value on the day you received them. These go in the "Other income" section, separate from your CGT.

Business activity. Trading, mining, or running an exchange as a business is reported as business income, not CGT. It is a smaller group, and if it is you, a registered tax agent is worth the call.

For the detail on each, the Australian crypto tax guide walks through the rules, and the DeFi tax guide covers the on-chain activity the exchanges never report.

Why it pays to get ahead of it

You do not want to be reacting to a letter. Acting before the ATO contacts you is cheaper, for two reasons.

You lose less. If you are behind on past years, coming forward voluntarily changes what you pay. Under the ATO's rules on voluntary corrections, if you disclose a shortfall before the ATO tells you it is examining your affairs, the base penalty is reduced by 80%. Where that shortfall is under $1,000, the penalty is reduced to nil. That discount only exists while you are ahead of them, and a data-matching letter is the moment the window starts closing.

You keep more. The instinct after learning the ATO has your data is to assume a big bill. Often it is the reverse, because accurate reporting works in your favour.

• Capital losses count. A rough few years in crypto may leave you with losses that offset your gains, but generally only if you report them. Unused losses carry forward to future years.
• You are taxed on the gain, so what you originally paid comes off the top. Leave your cost base out and you could overpay.

People who report from memory tend to leave money on the table. People who reconcile properly often owe less than they expected.

One thing to note if you hold for the long term: the 50% CGT discount on assets held over 12 months still applies to gains up to 30 June 2027, after which the rules change. That is a topic in its own right, and worth understanding before you plan any large disposals.

Where Summ comes in

Most of the work here is admin. Pulling years of transactions together and getting the cost base right across every account you have used. That is the part Summ takes off your plate.

Connect your exchanges and wallets and Summ imports your full history and categorises it for you. No spreadsheet, no manual matching. It tracks your cost base and AUD values across everything you have done, DeFi and self-custody included, so the report you hand over holds up if the ATO ever asks questions. That is the exact gap the data-matching program cannot see, filled in.

It also helps you not overpay. Summ flags the losses you can claim and applies the CGT discount where you are eligible, and there is a tax-loss harvesting tool built in for planning disposals. One subscription covers every prior year, which helps if you are catching up on returns you have missed.

Get started for free and import your transactions to generate a free report preview before you pay anything.

FAQ

Does the ATO really know about my crypto?
Assume it has a record of it. Australian exchanges report identity and transaction data to the ATO under its data-matching program, which covers the 2014-15 to 2025-26 financial years and up to 1.2 million people a year. It cannot see your full tax position, since it does not have your cost base or your self-custody wallets, but you should report as though it can already see your exchange activity, because it usually can.

What does the ATO actually receive from exchanges?
Your identity details and your transaction records from that exchange, including buys, sells, and the AUD values the exchange reports. It does not receive your cost base across platforms, your DeFi activity, or transfers between your own wallets.

Do I have to report crypto if I only made losses?
Yes, and you will usually want to. Capital losses are reported in the CGT section and can offset gains in the same year, with any excess carried forward. Not reporting them means giving up a deduction you are entitled to.

What happens if my return does not match the ATO's data?
A mismatch is the main way a routine data match becomes a review. If you lodge a return that does not line up with the exchange data the ATO holds, expect a follow-up. Reporting accurately the first time keeps you on the front foot.

Can I fix past years I did not report?
Yes. You can amend prior returns and make a voluntary disclosure. Coming forward before the ATO contacts you about a review can reduce penalties by up to 80%, and shortfalls under $1,000 have the penalty waived. A registered tax agent can handle the disclosure for you.

I already got an email from the ATO. What do I do?
Start with our step-by-step guide, I got an email from the ATO about crypto. What now?