Key Takeaways
- Australia’s move from the 50% CGT discount to cost-base indexation affects taxpayers differently depending on the asset’s original cost base.
- Property investors generally benefit from indexation because their assets typically have substantial purchase prices that can be adjusted for inflation.
- Startup employees often receive equity with minimal cost bases, leaving most of their capital gains fully exposed to tax despite indexation.
- The differing tax outcomes result from how the indexation formula operates rather than from differences in tax rates or policy intent.
- Subsequent policy carve-outs for innovative businesses recognize that a uniform tax rule may not produce equitable outcomes across all asset classes.
A single line in Australia’s 2026-27 federal budget replaced the 50% capital gains tax discount with cost-base indexation and a 30% minimum tax on net capital gains, effective from July 1, 2027. Applied to a residential property investor, that swap barely moves the needle. Applied to a startup employee cashing out equity, it roughly doubles the tax bill. Same rule, same formula, wildly different outcomes, and the reason comes down to a single number most people never think about: the cost base.
Indexation Assumes There’s Something to Index
Cost-base indexation works by adjusting what someone originally paid for an asset upward in line with inflation, then taxing only the gain above that adjusted figure. The logic holds up for an asset with a real starting price.
Picture a landlord who bought an investment property for $600,000 a decade ago. Indexed to inflation, that purchase price now sits closer to $780,000. Sell the property for $1 million, and tax applies to roughly $220,000 of real gain rather than the full $400,000 of nominal gain. Indexation did exactly its job: it stripped the inflation out of the gain and taxed what was left.
That mechanism depends entirely on the asset having a real, substantial cost base to begin with. SBS News reported that the May budget applied the same indexation formula uniformly across asset types, replacing the 50% discount for individuals, trusts, and partnerships alike, before later carve-outs began addressing the gap in how it landed on different kinds of capital.
Sweat Equity Starts From Almost Nothing
A startup employee’s cost base looks nothing like a landlord’s. Early equity is typically issued at cents per share, sometimes fractions of a cent, because the company has no revenue, no balance sheet, and no proven value yet. The employee isn’t buying an appreciating asset, but accepting below-market salary in exchange for a stake that might be worth nothing.
Run the indexation formula against that starting point and the maths breaks immediately. Multiply a near-zero cost base by any inflation factor and the result is still near zero. There is no figure worth adjusting upward, no real purchase price for inflation to act on, no shelter for the gain that follows.
Take an employee holding a 1% stake in a company that exits for $200 million. That stake is worth $2 million. Under the old 50% discount, the effective tax rate on that gain was around 23.5%, producing a tax bill of roughly $470,000 and leaving the employee with about $1.53 million. Under indexation applied to a near-zero cost base, almost the entire $2 million gain is exposed to the top marginal rate of close to 47%, pushing the tax bill to roughly $940,000. Same exit, same stake, nearly double the tax.
Same Formula, Opposite Outcomes
The landlord and the startup employee experience the identical policy mechanism in opposite ways. For the landlord, indexation provides real relief, because there’s a real number to index. For the employee, it provides almost none, because there’s nothing to inflate. The formula is neutral. The assets it’s applied to are not.
Bloomberg reported that even Productivity Commission chair Danielle Wood, while describing the broader budget as a credible package of productivity reform, flagged the risk of unintended consequences for the startup sector specifically, an acknowledgment that the same tool can do different jobs depending on what it’s pointed at.
Mechanical Problem, Not a Policy Disagreement
This isn’t a dispute about whether startup founders deserve a tax break or whether property investors are taxed fairly, but a mechanical mismatch between a formula and the asset class it was applied to without adjustment. Indexation measures relief in proportion to the size of the original cost base, and a startup employee with no cost base to speak of is precisely the case the formula was never built to handle.
Subsequent carve-outs for innovative businesses have addressed part of this gap by preserving the old discount for qualifying companies and shareholdings. But the underlying mechanics explain why the conversation happened at all: a rule built to separate inflation from real gains works exactly as intended when there’s a real number to start from, and produces a very different result when there isn’t.
FAQs
What is cost-base indexation?
Cost-base indexation is a tax mechanism that adjusts an asset’s original purchase price to reflect inflation before calculating the taxable capital gain. By increasing the cost base, the system aims to tax only the portion of the gain that represents a real increase in value rather than inflation alone.
This approach generally provides greater benefits for assets that were purchased for significant amounts and held over longer periods of time.
Why does cost-base indexation affect startup employees differently?
Startup employees often receive company equity at a very low acquisition cost because the business is still in its early stages and has limited market value. Since the original cost base is minimal, applying inflation adjustments results in only a negligible increase to that figure.
As a result, nearly the entire value realized when the shares are eventually sold may remain subject to capital gains tax, producing a much larger tax liability than for assets with higher purchase prices.
Why do residential property investors typically benefit more from indexation?
Investment properties usually have substantial purchase prices that can be adjusted upward to reflect inflation over the holding period. This higher indexed cost base reduces the amount of gain that is ultimately subject to tax when the property is sold.
Because inflation adjustments are applied to a meaningful original investment amount, property owners often receive considerably more tax relief than investors whose assets began with very small cost bases.
Does the different outcome mean the tax policy is unfair?
The differing outcomes primarily arise from the mechanics of the formula rather than from differing tax rates or explicit policy preferences. Cost-base indexation was designed to remove inflationary gains, but its effectiveness depends heavily on the size of the original acquisition cost.
When applied uniformly across assets with vastly different cost bases, the same calculation can produce significantly different practical results.
Have any changes been made to address the impact on startup equity?
Following concerns about the effect of the reforms on Australia’s startup ecosystem, subsequent policy carve-outs were introduced for certain innovative businesses and qualifying shareholdings. These measures were designed to reduce some of the unintended consequences for startup founders and employees.
Even with these adjustments, the discussion highlights the importance of considering how tax formulas interact with different asset classes rather than assuming a single rule will produce similar outcomes for every taxpayer.