Selling Your Investment Property? Five Legal Ways to Shrink the Tax Bill

A mate of mine sold his investment property last year. Made $200,000 on paper. Thought he was laughing. Then his accountant called.

After capital gains tax, selling costs, and the depreciation clawback, he kept about $118,000 of that $200,000. His face when I told him there were at least three things he could have done differently — legitimately, legally — to keep another $25,000 to $40,000? Let's just say the beer went flat.

Capital gains tax is the single biggest expense most property investors will ever face. Bigger than stamp duty. Bigger than agent fees. And unlike those costs, CGT is actually reducible — if you plan ahead.

Here are five strategies that are perfectly legal, well-documented by the ATO, and routinely missed by investors who only talk to their accountant once a year.

Strategy 1: Hold for twelve months and one day

The most basic CGT reduction — and the one most people know about — is the 50% CGT discount for assets held longer than twelve months 1.

If you buy a property on 1 January 2021 and sell it on 2 January 2022 or later, only half of your capital gain is added to your taxable income. Sell it on 31 December 2021? Full gain, full tax.

One day's difference can mean tens of thousands of dollars. On a $200,000 gain at a 39% marginal rate, the 50% discount saves you $39,000. That's not a rounding error — that's a year's worth of rent.

This seems obvious. But I've seen investors settle sales on day 360 because they were in a rush. Check. The. Calendar.

Strategy 2: How the 6-year rule can save you six figures

This is the strategy that most investors have never heard of, and it's worth more than all the others combined.

If you live in a property as your main residence and then move out and rent it, you can treat it as your main residence for up to six years — even though you're earning rental income from it 2. During those six years, any capital gain is completely tax-free. One hundred percent exempt.

The conditions:

• You must have actually lived in the property as your primary residence
• You cannot claim another property as your main residence during this period
• The six-year clock resets if you move back in, even briefly

Let's say you bought your home for $600,000, lived in it for two years, then rented it out. Six years later, it's worth $900,000. You sell. Capital gain: $300,000. Tax payable: zero.

Compare that to an investor who bought the same property as an investment from day one: $300,000 gain, 50% discount = $150,000 taxable. At 39% marginal rate, that's $58,500 in tax 3.

The 6-year rule just saved you $58,500. Legally. With the ATO's blessing.

"The 6-year rule is the single most powerful CGT exemption available to ordinary Australians. But it requires planning — you can't retrofit it after the fact," says Yan Zhu, Co-Founder & Chief Data Officer at PremiumRea.

Strategy 3: Time your sale for a low-income year

Capital gains tax is calculated at your marginal tax rate. The gain is added on top of your other income for the financial year 4.

This means the same property sale can attract dramatically different tax depending on when you sell.

Scenario A: You sell during a year where you earn $150,000 salary. Your $100,000 taxable gain (after 50% discount) pushes you into the 45% bracket. Tax on the gain: approximately $40,000.

Scenario B: You sell during a year where you take a career break, go part-time, or retire. Your other income is $40,000. The same $100,000 gain is taxed starting from a much lower base. Tax: approximately $28,000.

Difference: $12,000 — for the exact same property, exact same gain, just different timing 5.

Planning a sabbatical? Switching careers? One partner taking parental leave? Sell the property in that financial year. The lower your other income, the less your gain gets taxed.

Strategy 4: Pump up your cost base

Your capital gain is calculated as sale price minus cost base. The higher your cost base, the lower your gain, the lower your tax.

Most investors know their purchase price goes into the cost base. What they don't know is that the ATO allows a long list of additional costs 6:

• Stamp duty paid at purchase
• Legal and conveyancing fees (both buying and selling)
• Buyer's agent fees
• Capital improvements — renovations, extensions, granny flat construction (not repairs, but genuine improvements that add value)
• Building permit and council fees for any approved works

That $15,000 bathroom renovation? It increases your cost base by $15,000. The $110,000 granny flat you built? Straight into the cost base. The $800 building inspection you paid for before purchasing? Cost base.

Keep every receipt. Every invoice. Every contract. For the entire duration of ownership. Your accountant will thank you at sale time.

"I've seen investors lose $10,000 to $20,000 in unnecessary CGT simply because they didn't keep records of capital improvements over the years. A folder of invoices is worth real money," says Yan Zhu.

Strategy 5: Contribute more to super in the year you sell

This one is elegant. In the financial year you sell a property, you can make additional concessional contributions to your superannuation fund — up to the annual cap 7. These contributions are tax-deductible, which directly reduces your taxable income in the year the capital gain hits.

The effect: you're offsetting some of your capital gain with a tax deduction that simultaneously builds your retirement savings. The contribution is taxed at 15% inside super, rather than your marginal rate of 32.5% to 45%.

It's not a silver bullet — the annual contribution cap limits how much you can offset. But combined with the other four strategies, it's another $3,000 to $7,000 shaved off the bill.

Put them all together

None of these strategies works in isolation. The real power is stacking them.

Live in the property first → rent it out → hold for at least 12 months → sell in a low-income year → claim all capital improvements in your cost base → top up super in the sale year.

A $300,000 capital gain that would cost $58,500 in tax under the basic 50% discount could cost as little as $15,000 to $25,000 with proper planning. Or zero, if the 6-year rule applies.

The catch: all of this requires forward planning. You can't apply the 6-year rule retroactively. You can't reconstruct lost invoices. You can't change the settlement date after contracts are exchanged.

Talk to your accountant before you list the property, not after you've sold it. The conversation costs you an hour. The savings could fund your next deposit.