Managing cash flow is a balancing act for many businesses, particularly as economic conditions, profitability and operating costs change throughout the year.

One way businesses can improve cash flow is by varying their PAYG instalments when their expected income changes. This is a legitimate option available under the tax system and can help ensure tax payments better reflect actual business performance.

However, varying PAYG instalments isn’t simply about paying less tax today. Any variation should be based on a reasonable estimate of your expected tax liability. Reducing instalments too aggressively may result in additional interest charges and increased scrutiny when your annual tax return is lodged.

Understanding PAYG Instalments

PAYG instalments are designed to spread your income tax payments across the financial year rather than leaving you with a significant tax bill after lodging your tax return.

If your business experiences changes in profitability, seasonal fluctuations or unexpected events, varying your instalments may allow your tax payments to better align with your expected income.

The ATO recognises that business conditions change. What it expects is that any variation is supported by current financial information and reasonable assumptions rather than simply being used to defer tax payments.

Why the ATO Is Paying Attention

The ATO continues to monitor PAYG instalment variations, particularly where reduced instalments result in significant tax shortfalls at the end of the financial year.

Recent draft guidance (PCG 2026/D3) reinforces the ATO’s expectation that taxpayers use reliable financial information, current business performance and reasonable forecasts when determining whether a variation is appropriate.

While the guidance remains in draft form, it reflects the ATO’s broader focus on encouraging accurate instalment estimates and reducing significant year-end tax shortfalls.

Understanding the 85% Rule

When your income tax return is lodged, the ATO compares the PAYG instalments you’ve paid during the year with your actual tax liability.

Generally, if your instalments are less than 85% of your final tax liability, additional charges may apply.

Potential consequences include:

• General Interest Charge (GIC) on the shortfall
• administrative penalties in certain circumstances
• greater scrutiny of future PAYG instalment variations.

This doesn’t mean businesses should avoid varying instalments altogether. Rather, it highlights the importance of ensuring any variation is based on reasonable and supportable estimates.

When Should You Consider Varying Your PAYG Instalments?

A PAYG variation may be appropriate where your business circumstances have genuinely changed.

Examples include:

• profits are significantly lower than expected
• major clients have been lost
• seasonal conditions have affected revenue
• significant one-off business expenses have occurred
• trading conditions have changed substantially.

The key is ensuring your revised instalments reflect your expected tax position as accurately as possible based on the information available at the time.

Supporting Your Decision

Good record keeping plays an important role in supporting any PAYG variation.

If you decide to vary your instalments, it’s worth retaining documentation that explains how the revised amount was calculated, including:

• current management reports
• cash flow forecasts
• profit projections
• notes explaining significant changes in business performance.

Keeping this information on file can help demonstrate that your variation was based on reasonable assumptions if questions arise later.

Practical Tips for Managing PAYG Variations

If you’re considering varying your PAYG instalments this financial year:

• review your financial performance regularly rather than relying on historical figures
• prepare realistic profit forecasts before lodging a variation
• avoid reducing instalments simply to improve short-term cash flow
• reassess your position during the year if business conditions change again
• seek professional advice before making significant adjustments.

Taking a proactive approach can help you manage cash flow while reducing the risk of unexpected tax liabilities at year end.

How Supervision Group Can Help

PAYG instalment variations can be an effective cash flow management tool when they’re supported by accurate financial information and realistic forecasts.

At Supervision Group, we help businesses review their financial performance, prepare tax projections and determine whether varying PAYG instalments is appropriate for their circumstances. We can also help you document the basis for any variation and monitor your tax position throughout the year.

If your business circumstances have changed, or you’d like greater confidence that your PAYG instalments reflect your expected tax liability, we’d be pleased to help you review your position and plan ahead.