Australia prices honesty on a clock. Come forward before the ATO tells you it is examining you, and the shortfall penalty is typically reduced by 80%. Come forward after, and the reduction drops to around 20%. Same facts, same tax, same interest — the difference is almost entirely when you moved. With the data-matching program holding a decade of exchange records, that clock is not theoretical.
First: which instrument
Amendment. For returns inside the amendment period — broadly two years for individuals with simple affairs, four years for others, counted from the notice of assessment — a corrected return fixes the year: extra tax, interest, and penalties assessed on the shortfall, softened by the voluntary reductions below. Most crypto corrections for recent years live here.
Voluntary disclosure. For years outside the amendment window, multiple years at once, or anything with a serious behaviour question, the route is a voluntary disclosure to the ATO — same arithmetic of tax and interest, with the penalty outcome driven by behaviour and, above all, timing. Where the omission involved deliberate concealment, the amendment window may effectively never close against you — fraud and evasion have no time limit — which is one more reason those facts belong with an adviser before anything is filed.
The penalty arithmetic, honestly
Shortfall penalties are set as a percentage of the tax shortfall by behaviour: broadly 25% for failing to take reasonable care, 50% for recklessness, 75% for intentional disregard. Then timing acts as a multiplier on that number: a voluntary disclosure before you are notified of an examination generally cuts the base penalty by 80% — often taking a careless-behaviour case to a nominal figure — while disclosure after notification earns around 20% at best. Interest (currently charged daily as GIC) runs regardless, from when each year's tax was originally due, and — a 2025 change worth knowing — that interest is no longer tax-deductible. Time is literally the price.
Every stage of the letter sequence — prompt, data-matching letter, review — is the 80% discount visibly expiring. The cheapest version of this event is always the one initiated by you.
The sequence
- Reconstruct all affected years before filing anything. Every platform, every wallet, AUD values per disposal, parcels and their discount clocks, income events at receipt value. A disclosure that has to be reopened is worse than one filed a month later.
- Characterise behaviour with an adviser, not a mirror. Careless, reckless, or intentional is a legal characterisation that sets the base penalty and the assessable years — people self-assess to both extremes, and both are usually wrong.
- Check what the ATO already holds. Prefill data and any prior letters shape whether a disclosure reads as voluntary candour or as confirming what was already found. This changes tone and sometimes route — it should never change the decision to disclose.
- File the years together, in one coherent story. Amendments and disclosures across years should reconcile with each other and with the exchange data. Internal contradictions are what turn corrections into reviews.
- Arrange payment — or a plan — at lodgment. Payment arrangements exist and are routine; silence after an admitted debt is not.
If a review or audit letter has already arrived
The 80% moment has passed; the 20% moment has not. Full cooperation, complete reconstruction and prompt disclosure inside an examination still land materially better than obstruction — and the reconstruction is the same work either way. What changes is only who is holding the pen when the numbers first appear. From this point, representation first: scope, sequencing and every written word now matter in a way they did not last month.
Behaviour and penalty outcomes are legal characterisations made on facts this page does not have. It frames the decision; it does not make it, and reading it creates no professional relationship.