%22%20d%3D%22M50.5%2036.41A25%2025%200%200%201%2036.41%2050.5L31.27%2037.48A11%2011%200%200%200%2037.48%2031.27Z%22%2F%3E%0A%3C%2Fsvg%3E){kind=small}
Why an ETF's cost base moves
An AMIT fund works out how much of its income and gains belongs to each unit, and you pay tax on that whether or not it was paid out. When the cash you got is more than what was attributed to you, the difference is an excess and your cost base goes down. When it's less, that's a shortfall and the cost base goes up.
The adjustment happens at the end of each financial year, or just before you sell if that comes first. Brokers don't track it, so the cost base on your trade confirmations drifts further from the real one every year you hold.
How the calculator works
For each distribution it takes the fund's net amount for a unit, from the issuer's own AMIT figures where they give them or from the tax components where they don't, and applies it to the units you held on the ex date. A unit bought on the ex date or later misses that distribution. Sales come out of your oldest parcel first unless you pick one.
If a decrease is bigger than a parcel's cost base, the cost base stops at nil and the rest is a capital gain for that year. The calculator shows it against the year so you can report it.
Questions
Where are the AMIT figures on my tax statement?
On the annual AMMA statement from the fund, in a line called AMIT cost base net amount. It says excess when your cost base goes down and shortfall when it goes up. The calculator uses the same figures, one distribution at a time.
Why would my cost base go up?
When the fund attributes more income or gains to you than it paid out, you're taxed on money you never received. The cost base goes up by the difference so you aren't taxed on it again when you sell.
How do I add units from a DRP?
Each reinvestment is a new purchase. Add it with the payment date, the units you got and the DRP price, and leave brokerage at zero. It's a separate parcel with its own 12 month clock.
What does Estimate mean next to a year?
Funds publish estimated components when they pay a distribution and the final ones on the AMMA statement after 30 June. Until the finals are out, that year's adjustment can still change, usually by a little.
When does the 50% discount apply?
On a sale up to 30 June 2027, when there are at least 12 months between the day you bought and the day you sold, not counting either day. Individuals and trusts get 50% off the gain and super funds a third. From 1 July 2027 individuals and trusts index their cost base for inflation instead, and can choose to lock in the gain up to that date at the old discount. Super funds keep their third, and companies don't get a discount either way.
Is this tax advice?
No. It works the numbers out from the fund's published components and the trades you enter. Check anything you're lodging with your accountant or tax agent, especially if a decrease has gone past nil.