The Australian Taxation Office (ATO) can flag your crypto activity before you even enter a figure in your tax return. For example, its 2024-25 myTax return pre-fills an indicator that you may have a crypto capital gains tax event. If the information you report does not match what the ATO expects, it may result in a notice of amended assessment, which is the ATO’s revised tax bill for that year.
If you have received one, knowing what happens next is important. This guide explains what the notice contains, how much the amendment could cost and how to respond before the deadline. It also covers the steps you can take to check your other tax years and reduce the risk of the same issue arising again, based on ATO guidance.
Key Takeaways
- The extra tax falls due 21 days after the ATO issues the notice of amended assessment.
- Shortfall interest applies to the extra tax, and a penalty of 25% to 75% may follow.
- A review request does not extend your objection deadline, so note that date straight away.
- Keep every crypto record for five years, and long enough to cover your amendment period.
What Is A Notice Of Amended Assessment For Crypto?
A notice of amended assessment is the formal document the ATO issues when it changes the figures in your tax return. For crypto, this can happen when the information you reported does not match data the ATO receives from third parties. The notice then shows the revised tax amount, including any additional tax you owe.
What The Notice Contains?
The notice lists the extra tax you now owe and explains how to pay it. It also shows any shortfall interest charge, already calculated for you. Every figure comes from the corrected return. That makes the notice the first document to check, so keep it beside all your crypto records.
Why The ATO Amends Crypto Returns?
The ATO may amend a return when it finds a discrepancy between your tax return and third-party data. For crypto, the process generally works like this:
- The ATO Receives Crypto Data: Designated data providers, such as crypto exchanges, can provide information including account balances, transaction dates, asset types and linked bank details.
- The ATO Compares The Information: It matches this data against the information you reported in your tax return to identify potential errors or omissions.
- The ATO May Contact You First: If it finds a discrepancy, it may ask you to provide more information within the timeframe stated in its request.
- The ATO May Amend Your Return: If you do not respond within the stated timeframe, the ATO may issue a notice of amended assessment with the revised tax amount.
You may therefore receive a request for information before the amended assessment itself. Responding to that request on time gives you an opportunity to clarify the discrepancy before the ATO changes your assessment.
How Far Back The ATO Can Amend?
For most individuals, the ATO can generally amend an assessment within 2 years of issuing it. From the 2024-25 income year onwards, sole traders, including those running a crypto trading business, generally have 4 years. In exceptional cases, such as fraud or evasion, the ATO may amend an assessment beyond these limits.
These limits matter when your crypto activity spans multiple tax years. Check the date on each notice of assessment and calculate the applicable amendment period from the day after it was issued. Repeat this for every year you traded.
What Does A Notice Of Amended Assessment Cost You?
A notice of amended assessment can increase your tax bill in three ways. You may need to pay the extra tax, shortfall interest and, in some cases, a penalty. Each of these charges work differently. The tax has a payment due date, interest can apply from an earlier date, and the penalty depends on why the error occurred.
Extra Tax And The Due Date
The extra tax falls due 21 days after the ATO issues the notice of amended assessment. That leaves three weeks to decide whether to pay in full, arrange instalments or challenge the figures. Each choice depends on the records behind your original return. Start gathering them when the notice arrives.
Shortfall Interest Charge
The ATO applies shortfall interest charge (SIC) instead of general interest charge (GIC) on an amended shortfall. It runs from the date the tax was originally due until the ATO corrects the assessment. SIC then compounds daily. The ATO updates its rate every quarter using a formula set by law.
The ATO explains the choice simply. Taxpayers usually do not learn of a shortfall until the amended assessment arrives. Interest still accrues over the whole period, though. An old crypto year can therefore cost more than expected. Check the current SIC rate before you estimate what you might owe today.
Shortfall Penalties
A penalty may apply on top of tax and interest. The ATO calculates it as a percentage of the shortfall. That percentage reflects the behaviour behind the error. Generally, you will not be penalised if you or your agent took reasonable care. The same applies where you followed ATO advice.
Behaviour | Base Penalty Amount |
Failure to take reasonable care | 25% of the shortfall |
Recklessness | 50% of the shortfall |
Intentional disregard | 75% of the shortfall |
The base amount is only a starting point. The ATO can increase, reduce or waive the penalty based on the circumstances. Good records can also help show that you took reasonable care.
How To Respond To A Notice Of Amended Assessment For Crypto?
You have several ways to respond once the notice arrives, and each suits a different situation. Some routes accept the amount, while others challenge it or ask for relief. The ATO publishes a route for every one of them. This section explains how each route works and when it applies.
Step 1: Check Every Figure Against Your Records
Start by comparing the notice with your own transaction history, line by line. Note every disposal, date and cost base that the ATO changed. You can also contact the ATO to request a written explanation of any adverse adjustment. That explanation helps you see what the ATO changed and why.
Errors can come from missing wallet transfers, wrong cost bases or unrecorded swaps. The guide on common crypto tax filing mistakes shows where figures usually go wrong. Write down each discrepancy with its date and amount. A clear list makes every later step faster, whether you are paying, reviewing or objecting.
Step 2: Pay Or Arrange A Payment Plan
If you agree with the amended assessment amount, pay it by the due date. If you cannot, a payment plan may be possible. The ATO’s payment plan estimator helps you work out repayments. For debts of A$100,000 or less, online or phone setup may be available. Choose an amount you can sustain.
Step 3: Request A Review
You can ask the ATO to review the notice if you believe the amounts are incorrect or have information that was not previously available. Support your request with clear documents rather than explanations alone.
A review does not affect your right to object or extend the objection deadline. If the deadline is approaching, lodge your objection instead of waiting for the review outcome.
Step 4: Lodge An Objection
For an amended assessment, you have the later of two dates. One is 60 days after you are given the notice. The other is the time limit for the original assessment, which is two years for most individuals. A posted notice is treated as given seven business days after issue.
There is no fee to lodge. If you are vulnerable, Dispute Assist is a free service that supports individuals through the objection process. Attach the records behind your position, since evidence carries an objection. A well-organised transaction history also saves the ATO from asking you for the same details twice.
Step 5: Ask For Remission Of Interest Or Penalties
You can ask the ATO to remit shortfall interest in full or part where extenuating circumstances exist. One example is where the ATO contributed to the error. You must explain your reasons and provide evidence. The ATO reviews each application case by case, as set out in PS LA 2006/8.
Penalties follow a similar path through the remission of penalties process. The ATO considers whether events beyond your control prevented you from meeting your obligations. It also asks whether the penalty produces an unjust result. Remission must be fair and reasonable. It often decides before it advises you of the penalty.
How Can You Prevent Another Amended Assessment For Crypto?
Reconcile every open year now, and keep records that match what you report. Those two habits reduce the chance of another costly mismatch. The next two parts show how to correct earlier years while penalties can still be reduced. They also list the records the ATO expects you to hold.
Check Your Other Years
The notice covers one year, but your crypto activity probably spans several. Review each open year for the same omission. If you find one, tell the ATO yourself. A voluntary disclosure can cut the base penalty amount by 20%, 80% or, sometimes, to nil. Timing and the shortfall decide which.
The same window applies to your own requests. Beyond it, you may need to lodge an objection instead. The ATO also adds 20% to the base penalty if you knew of a shortfall. That applies where you did not tell it within a reasonable time. The guide on filing your crypto taxes covers correct reporting.
Keep The Records The ATO Expects
The ATO expects records of each crypto asset and every transaction. Each asset counts as a separate capital gains tax (CGT) asset. Keep them for five years from the latest of three dates. Those dates are record creation, transaction completion and the CGT event year. Hold at least these items:
- Receipts for each purchase, transfer or disposal
- The date of every transaction
- What each transaction was for and the other party, which can be just their crypto asset address
- Exchange records
- The Australian dollar value of the asset at the time of each transaction
- Agent, accountant and legal costs
- Digital wallet records and keys
- Software costs linked to managing your tax affairs
Export your transaction history at least every three months, and always before closing an account. Crypto is volatile, and platforms change or close. The ATO suggests a reputable Australian crypto tax calculator to sync your exchange and wallet accounts.
How Can KoinX Help With A Notice Of Amended Assessment For Crypto?
Disputing an amended assessment starts with proving your crypto gains, which can be difficult when your records are scattered. KoinX brings your transaction history together and calculates your gains based on ATO rules. You can then compare the results with the amended figures and quickly spot any differences in the ATO’s data.
The Transaction History Report works as a full, dated ledger of trades, transfers, rewards and fees. Use it to confirm that every transaction the ATO’s own data could reflect appears in your records. Transfers between your own wallets can look like disposals, so the ledger helps you explain them clearly.
Buy Sell Report
The Buy Sell Report lists every buy, sell and swap in one place. Reviewing it lets you verify trading activity and spot issues before you generate final reports. When the ATO questions a disposal, this is the quickest check. You can see at once whether you recorded it and when.
End Of Year Balance Report
The End Of Year Balance Report captures your closing crypto positions, their values and acquisition cost. You and your accountant can use it to reconcile holdings for the specific year the ATO amended. A gap between your closing balance and the ATO’s picture can flag a missing wallet or exchange.
ATO Complete Tax Report
The Complete ATO Tax Report applies ATO rules to your crypto data. It covers CGT discounts, income, derivatives and detailed portfolio balances. Compare its figures with the amended assessment. If they agree, you know where you stand. If they differ, you have a documented basis for a review or objection.
Do not wait for the due date to gather evidence. Add your crypto transactions to KoinX, run the four reports above and compare them with the amended figures. Pricing starts at A$28.99 for up to 25 transactions, with higher tiers for larger histories. You can therefore check the numbers before deciding how to respond.
Timing is the one lever you still control. The ATO names one example of extenuating circumstances. Paying the shortfall before it issues the notice can support a request to remit shortfall interest. That makes the months before your next return the cheapest time to fix an old year. Reconcile every disposal first.
Reconciling every open year by hand takes time most investors do not have. KoinX turns your transaction history into reports built on ATO rules, one financial year at a time. Sign up and compare each year with your ATO account. If the numbers disagree, you will find out early, while every option is still open.
Frequently Asked Questions
What Happens If I Miss The 21-Day Due Date?
Once the 21-day due date passes, general interest charge (GIC) may apply to any unpaid amount. Shortfall interest charge (SIC) covers the shortfall up to the amended assessment; GIC applies after that due date. A payment plan can still cover the balance, but contact the ATO early.
Can I Claim Shortfall Interest Charge As A Deduction?
Not for SIC incurred on or after 1 July 2025, because the law changed from that date. Earlier SIC remains deductible, but only in the income year you received the notice that included it. A remitted charge incurred after that date does not need to be declared as interest income either.
Can I Object To A Penalty Separately From The Assessment?
Yes. You have the latter of two dates. One is 60 days from the penalty assessment notice. The other is the last day to object to the related assessment. A refusal to remit shortfall interest can also be challenged within 60 days. That applies only where the interest exceeds 20% of the shortfall.
Am I Still Liable For Penalties If My Tax Agent Made The Error?
You may not be. Under the safe harbour rules, no penalty applies if all three conditions are met. Your registered tax agent made the statement. You gave them all the relevant information. The error came from their failure to take reasonable care. You must be able to prove you supplied the information.
