As the end of the financial year approaches, many investors review their portfolios with a view to managing tax outcomes. In this article, director of Tax Communications at H&R Block (NYSE:HRB) Australia, Mark Chapman, looks at one strategy that often comes up in this context: “tax loss harvesting”—selling underperforming assets to realise capital losses and offset gains elsewhere.
While this is a legitimate strategy, it can quickly cross into problematic territory if it involves so-called “wash sales.” The Australian Taxation Office has made it clear that wash sales are on its radar, and investors who engage in them risk having losses denied, penalties applied, and increased scrutiny.
So what exactly is a wash sale, and how do Australia’s anti-avoidance rules apply?
What is a Wash Sale?
A wash sale typically involves selling an asset to crystallise a capital loss, and then repurchasing the same—or a substantially identical—asset shortly before or after the sale.
From a commercial perspective, the investor’s economic position hasn’t materially changed. However, from a tax perspective, they’ve created a capital loss that can be used to offset gains.
For example:
- An investor sells shares in a listed company at a loss on June 28
- The same shares are repurchased on 1 July
- The investor claims the capital loss in their tax return
While this might appear to be a clever bit of timing, the ATO may view it as a wash sale if the dominant purpose was to obtain a tax benefit.
The role of anti-avoidance rules
Australia’s tax system includes broad anti-avoidance provisions designed to prevent arrangements that are technically compliant but undermine the intent of the law.
The key provision is Part IVA of the Income Tax Assessment Act. Under Part IVA, the ATO can cancel a tax benefit if:
- There is a scheme or arrangement
- A tax benefit is obtained
- The dominant purpose of entering into the scheme is to obtain that tax benefit
Wash sales fall squarely within the types of arrangements that Part IVA is designed to address.
How the ATO identifies wash sales
The ATO uses a combination of data matching, analytics, and transaction-level reporting to identify potential wash sale activity.
Red flags include:
- Selling and repurchasing the same asset within a short timeframe
- Transactions occurring just before or after 30 June
- No material change in the investor’s economic exposure
- A pattern of similar behaviour across multiple years
Importantly, the ATO doesn’t rely solely on timing. It looks at the broader context, including the investor’s intent and whether there was a genuine commercial rationale.
“Substantially identical” assets
A common misconception is that wash sale rules only apply if you buy back the exact same asset. In reality, the ATO may also consider assets that are 'substantially identical'.
For example:
- Selling units in one ETF and buying another ETF that tracks the same index
- Selling shares in a company and buying derivatives that replicate the same exposure
If the replacement asset effectively puts you back in the same economic position, the ATO may still apply anti-avoidance rules.
Consequences of getting it wrong
If the ATO determines that a wash sale has occurred, the consequences can be significant:
- Denial of the capital loss: The loss may be disregarded entirely
- Amended assessments: Your tax return may be revised
- Penalties and interest: Administrative penalties can apply, along with interest on unpaid tax
- Increased scrutiny: Future returns may attract closer attention
These outcomes can outweigh any perceived short-term tax benefit.
Legitimate tax loss harvesting
It’s important to distinguish between wash sales and legitimate tax planning.
Selling an asset at a loss to rebalance your portfolio, reduce risk, or exit a poor investment is generally acceptable—even if it has tax benefits. The key difference is intent and substance.
To stay on the right side of the rules:
- Ensure there is a genuine commercial reason for the sale
- Avoid immediate repurchase of the same or similar asset
- Consider waiting a reasonable period before reinvesting
Diversify into different assets rather than replicating the same exposure
For example, selling shares in one sector and reinvesting in a different sector is less likely to raise concerns than selling and immediately buying back the same shares.
Timing around June 30
The end of the financial year is when wash sale activity is most likely to occur—and when the ATO is most vigilant.
Investors often look to:
- Realise capital losses before 30 June
- Offset gains realised earlier in the year
- Reset cost bases for future investments
While these are valid considerations, transactions that appear driven purely by tax outcomes—particularly those with minimal time between sale and repurchase—are more likely to be challenged.
Record-keeping and documentation
One of the best defences against an ATO challenge is strong documentation.
Investors should be able to demonstrate:
- The commercial rationale for selling an asset
- Investment strategy changes or portfolio rebalancing decisions
- Timing considerations unrelated to tax
Keeping clear records can help substantiate your position if the ATO raises questions.
Crypto and wash sales
Wash sale principles are not limited to shares—they also apply to other capital assets, including cryptocurrency.
Given the high frequency of crypto trading, investors may inadvertently trigger wash sale concerns by:
- Selling and repurchasing the same token within short periods.
- Switching between similar tokens with correlated price movements.
The ATO has increased its focus on crypto transactions, making it even more important to approach tax loss harvesting carefully in this space.
Practical Example
Consider an investor who holds shares that have declined in value:
- They sell the shares on 29 June, crystallising a $20,000 loss
- On 2 July, they repurchase the same shares at a similar price
- There is no change in their investment strategy or market outlook
In this case, the ATO may conclude that the dominant purpose was to obtain a tax benefit, and apply Part IVA to deny the loss.
By contrast, if the investor sold the shares to exit a sector and reinvested in a different asset class, the outcome would likely be different.
A balanced approach
Tax efficiency is an important part of investing—but it should not override sound investment principles.
The ATO’s focus on wash sales highlights the importance of aligning tax strategies with genuine commercial decisions. Investors who take a disciplined, long-term approach are less likely to run into issues.
Conclusion
Wash sales may seem like a simple way to reduce your tax bill, but they carry significant risk under Australia’s anti-avoidance rules.
With increased data matching and scrutiny from the Australian Taxation Office, investors should assume that aggressive tax-driven strategies will be detected.
The key is to ensure that any decision to sell and reinvest is grounded in genuine investment logic—not just tax outcomes. By doing so, you can manage your tax position effectively while staying firmly on the right side of the rules.
About the author
With over 30 years of experience as a tax professional in both the UK and Australia, Mark Chapman has established himself as a leading expert in taxation for individuals and small to medium-sized enterprises (SMEs). Currently serving as the director of Tax Communications at H&R Block Australia, Mark has been with the company since 2015, where he plays a pivotal role in shaping and delivering tax advice across various media channels.