How corporate actions affect your tax in Australia

Your purchase records say 1,000 shares. Your broker says 2,000. Or the company you bought doesn't exist anymore and your holding has a new name.

That gap is almost always a corporate action: a split, a merger or a reinvested dividend your trade history never recorded. Here's what the common ones do to your cost base, and how Summ handles them for you.

What is a corporate action?

It's something a company does that changes the shares you own: how many you have, what they're called, what they're worth, or whether they still exist. You don't have to do anything. It just happens to your holding.

Nearly all of them matter for tax, because they change the number of shares your cost base is spread across, the cost base itself, or both.

Why they cause tax errors

Capital gains tax works parcel by parcel, and corporate actions change your parcels without a trade:

• The share count changes. After a 2-for-1 split, 500 shares bought for $10,000 become 1,000 shares that still cost $10,000. Miss the split and you've got 500 shares with nothing behind them.
• The cost base changes. A capital return lowers it. A demerger splits it across two companies.
• One holding becomes another. In a merger your A shares become B shares, so your history shows A bought and never sold, and B held but never bought.

Broker exports rarely capture any of this reliably, which is why tools that just replay your trades get it wrong.

The common ones at a glance

Corporate action	What happens	What it generally means for tax	What Summ does
Dividend	Company pays cash per share	Income in the year it's paid, plus franking credits. No cost base change	Added automatically, with franking credits and tax withheld
Special dividend	A one-off dividend	Taxed as a dividend	Added automatically
ETF or trust distribution	Fund pays out its income	Taxed by component from the AMMA statement, which can also adjust your cost base	Distribution added automatically; upload the AMMA statement for the cost base adjustment (see our AMMA guide)
DRP	Dividend paid as new shares	Still income. The new shares are a new parcel costing the amount reinvested	Once you set up the plan, Summ records the income and the new parcel
DSSP	Dividend that gets paid out as a bonus share rather than cash	Generally not income. Your cost base spreads across the bigger holding	Recorded as bonus shares once you set up the plan
Split	A company divides its existing shares into multiple new shares.	Not a CGT event. Cost base spread across more shares	Added automatically
Consolidation	Several shares become one	Not a CGT event. A split in reverse	Added automatically
Bonus issue	Free extra shares	Generally not income. Cost base spreads across the bigger parcel	Added automatically where the event is in our data
Capital return	Company hands back capital	Not income. Lowers your cost base, and anything above it is a capital gain	Added automatically
Ticker or name change	Same company, new code	Not a CGT event	Carried across automatically as the same holding
Merger or takeover	A shares become B shares, cash or both	A CGT event, though scrip-for-scrip rollover can defer the gain on the share part	Added automatically from the deal terms
Demerger	Part of A becomes a separate company	Cost base split between the two using the company's published ratio. Rollover relief may apply	Added automatically, using the published ratio

Why Summ doesn't rely on your broker's rows

Summ doesn't use the corporate-action rows in your broker export. It picks up the events from market data and applies them to your holdings itself. That way the same event looks the same whether you imported from CommSec, Stake, Pearler, Interactive Brokers or a spreadsheet, and whether you bought last month or years ago.

What this guide doesn't cover

Some corporate actions depend on a choice only you know about, like taking up a rights issue, selling into a buyback, or picking cash or shares in a takeover. Those aren't covered here.

Options, CFDs, short selling and employee share schemes like RSUs and ESPPs aren't handled automatically either.

How Summ handles your corporate actions

Import your broker history by CSV and Summ handles dividends, distributions, splits, consolidations, capital returns, demergers, ticker changes, mergers and special dividends for you. Set up your DRP or DSSP once and it applies to every dividend after that. You end up with a parcel history that reconciles, and one ATO-ready report for your shares and crypto.

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Frequently asked questions

Is a share split taxable in Australia? Generally no. You have more shares but the same total cost base, and each parcel keeps its original purchase date.

Does a ticker change trigger CGT? Generally no. You haven't sold anything, the code has just changed.

Is a reinvested dividend taxed? Yes. It's income in the year it's paid, the same as a cash dividend, and the new shares are a new parcel.

Why does my broker show a different number of shares from my records? Almost always a corporate action. A split, consolidation, DRP or bonus issue changed the count without a trade.

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This article is general information about how common corporate actions are usually treated under Australian tax rules. It is not tax, financial or legal advice, does not take your circumstances into account, and should not be relied on to work out your own tax position. Speak to a registered tax agent about your own holdings.