The ATO’s ability to identify discrepancies in taxpayer records has increased significantly. Bank deposits, overseas transfers and major asset purchases are now routinely tracked and analysed.

When something cannot be explained, the consequences can be significant.

In this episode of Explain That by Velocity Legal, Andrew Henshaw is joined by Rajan Verma to discuss how unexplained income is treated and why these cases are becoming more common.

What Is Unexplained Income?

Unexplained income refers to amounts received by a taxpayer where there is no clear or identifiable source.

This can include:

• cash deposits into bank accounts
• overseas transfers
• unexplained increases in assets
• transactions without supporting records

When the ATO identifies these amounts, it must determine whether they are taxable. If the nature of the amount cannot be established, the issue shifts to the taxpayer.

The Reverse Onus of Proof

A key feature of these cases is that the burden of proof rests with the taxpayer.

The ATO does not need to prove that an amount is income. Instead, the taxpayer must demonstrate what the amount represents and why it is not taxable.

If that cannot be done, the amount is treated as income.

This creates a significant challenge, particularly where transactions occurred years earlier or where records were not maintained.

Why Unexplained Income Cases Are Increasing

Several factors are driving the increase in unexplained income cases:

• improved data matching across government agencies
• access to bank records and financial information
• tracking of international transfers through AUSTRAC
• increased use of data analytics and AI
• additional funding for ATO compliance programs

The ATO is also focusing on the private market, where a significant portion of the tax gap is believed to sit.

Default Assessments and Their Impact

In more serious cases, the ATO may issue a default assessment.

This occurs where the ATO does not accept the taxpayer’s records or where no return has been lodged. The ATO effectively determines what it believes the taxpayer’s income to be.

Default assessments are difficult to challenge. It is not enough to say the ATO is wrong. The taxpayer must positively prove what the correct position should have been.

These assessments also attract significant penalties, including a 75 percent penalty on the assessed tax, plus interest.

Why Taxpayers Struggle to Defend These Cases

Most unsuccessful cases share a common issue: a lack of evidence.

Common explanations include:

• gifts from family members
• funds transferred from overseas
• informal financial arrangements

However, without contemporaneous documentation or third party evidence, these explanations are difficult to substantiate.

Courts and tribunals require clear and reliable evidence. Assertions alone are not sufficient.

Practical Steps for Taxpayers

The most effective strategy is prevention.

Taxpayers should:

• avoid cash transactions where possible
• ensure funds are transferred through traceable channels
• retain bank records and supporting documentation
• document gifts or loans at the time they occur
• maintain accurate business records where relevant
• seek professional advice when uncertainty arises

Contemporaneous documentation is critical. It is far easier to explain a transaction when it occurs than several years later.

The Takeaway

Unexplained income cases highlight a fundamental principle of the tax system.

If you cannot prove where your money came from, it will be treated as income.

For taxpayers, the key is not only understanding the law, but maintaining the records needed to support their position.

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🎧 Watch the full episode of Explain That by Velocity Legal for a practical discussion of unexplained income and ATO risk.

For advice on ATO audits, tax disputes or unexplained income issues, contact Velocity Legal’s Tax team.