Cost base of shares: brokerage and what to include

• Brokerage isn't a tax deduction for an investor. It goes in the cost base instead.
• A return of capital from the company lowers your cost base.
• Bought the same shares at different times? Each purchase has its own cost base.

• The price you paid for the shares.
• Brokerage on the purchase, and later on the sale, GST included.
• Fees for advice or legal work on that purchase or sale.

Not included: anything you have already claimed as a deduction, and the cost of investment courses or seminars.

For overseas shares, convert the price and the brokerage to Australian dollars at the exchange rate on the day of the trade.

The ATO's own example:

• Fred buys 1,000 shares at $5 each, $5,000, and pays $50 brokerage.
• When he sells them, he pays another $50 brokerage.

Cost base: $5,000 + $50 + $50 = $5,100.

If he sells for $6,000, his gain is $6,000 − $5,100 = $900, before any discount.

• A return of capital. A payment from the company that isn't a dividend comes off your cost base. If it is more than your cost base, the extra is a capital gain.
• ETF annual tax statements. An ETF's statement after 30 June can show a cost base increase or decrease for the year. Adjust your cost base by that amount.
• Dividend reinvestment. Each reinvestment is a new purchase, with the reinvested dividend as its cost.
• Splits and consolidations. The total cost stays the same, spread over the new number of shares.
• Bonus shares, rights issues, demergers and buy-backs. Each has its own rules, and the company usually publishes a tax guide for its holders. Check the ATO's guidance for the event.

If you bought the same shares at different times, each purchase is a separate asset with its own cost and date. When you sell only some, you need to say which ones you sold.

With your holding statements, you can pick which shares you sold. If you can't tell, the ATO accepts treating the ones you bought first as sold first.

The choice changes your gain, and whether the 12-month discount applies. Selling shares you bought at a higher price gives a smaller gain. Keep a record of what you chose.

• Buy and sell confirmations, with dates, prices and brokerage.
• Holding statements from CHESS or the share registry.
• Dividend reinvestment statements, and ETF annual tax statements.
• Notices of returns of capital, splits and other company events.

Keep them for five years after you sell, and longer if a loss from the sale is still being carried forward.

Can I claim brokerage as a tax deduction?

Not if you are an investor. It goes in your cost base, which lowers your gain when you sell.

I've lost my purchase records. What now?

Ask your broker for past confirmations, or the share registry for your holding history. Both keep records for years.

Do I include GST on brokerage?

Yes, if you can't claim the GST back, which most individual investors can't. Use the full amount you paid.

Upload the file from your broker and Portfoli.au keeps the price, date and brokerage of every purchase, converting overseas trades at that day's exchange rate. Enter an ETF's annual tax statement and its cost base change is applied.

You choose which shares count as sold: oldest first, newest first, the purchases that give the smallest gain, or your own pick each time. The gain on every sale is shown step by step.

Try the free capital gains calculator, or start free.

• ATO, Personal investors guide to capital gains tax, part B
• ATO, Cost base of assets
• ATO, Keeping records of shares and units (updated 22 June 2026)

Check with a registered tax agent before you act.

• Capital gains tax on shares in Australia: When you pay tax on selling shares or ETFs, how the gain is worked out, and what to do with a loss.
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• Capital gains tax changes from 1 July 2027: The 50% discount is replaced for growth after 1 July 2027. What that means for shares you own now.
• Tax-loss selling before 30 June, and wash sales: Selling at a loss before 30 June, what the loss is worth, and the buy-back the ATO refuses.
• How ETFs are taxed in Australia: Distributions, the annual tax statement, cost base changes, and selling units.
• How to track your share portfolio in Australia: The records to keep, a spreadsheet or a tracker, and the figures worth watching.
• All guides, and help with using Portfoli.au.
• Capital gains calculator: work out the gain on one sale, free.
• Dividend calculator: estimate dividend income with franking credits, free.