Indexation vs the 50% Discount: A Wimmera Worked Example
Ten years of real CPI figures, run through both methods.
With the 50% Capital Gains Tax discount being replaced by an inflation-indexed cost base, the obvious question is how differently the two methods actually behave. Not in theory — on a real block of land, with the CPI figures the Australian Bureau of Statistics actually published.
So here is a Wimmera farming land example, run both ways.
The land
A farmer buys 250 acres of Wimmera cropping country in June 2015 for $500,000. Ten years later, in June 2025, it sells for $1,750,000. Purchase and selling costs are ignored to keep the comparison clean.
That is $1,250,000 of growth over ten years — a 250% increase, or a little over 13% a year compounding.
How indexation builds the cost base
Indexation lifts what you paid by the movement in the Consumer Price Index. Because the CPI is published quarterly, the calculation uses the index number for the quarter the money was spent and the quarter of the sale. Taking the June quarter each year, here is how the $500,000 would have grown.
June quarter CPI Factor Indexed cost base
June 2015 107.5 1.000 $500,000
June 2016 108.6 1.010 $505,000
June 2017 110.7 1.030 $515,000
June 2018 113.0 1.051 $525,500
June 2019 114.8 1.068 $534,000
June 2020 114.4 1.064 $532,000
June 2021 118.8 1.105 $552,500
June 2022 126.1 1.173 $586,500
June 2023 133.8 1.245 $622,500
June 2024 138.8 1.291 $645,500
June 2025 141.7 1.318 $659,000
ABS Consumer Price Index, All Groups, weighted average of eight capital cities (2011–12 = 100). Factors calculated from June 2015, rounded to three decimals.
Note how flat the early years are. Between 2015 and 2020 the cost base creeps up by barely $32,000, because inflation over that stretch was close to non-existent. The 2021 to 2023 spike does more work in three years than the previous six managed between them. Even so, a full decade only adds $159,000 to what the farmer is treated as having paid — while the land itself went up by $1,250,000.
Method one: halve the gain
An individual or trust holding the land more than twelve months takes the gain and cuts it in half.
Sale price $1,750,000
Less cost base ($500,000)
------------
Capital gain $1,250,000
Less 50% discount ($625,000)
------------
Taxable capital gain $625,000
Method two: index the cost base
Nothing is halved. Instead the $500,000 becomes $659,000, and the whole remaining gain is assessable.
141.7 ÷ 107.5 = 1.318
$500,000 × 1.318 = $659,000
Sale price $1,750,000
Less indexed cost base ($659,000)
------------
Taxable capital gain $1,091,000
Side by side
Method Taxable gain Tax at 47%
50% discount $625,000 $293,750
CPI indexation $1,091,000 $512,770
Difference $466,000 $219,020
Tax shown at the top marginal rate including Medicare levy, applied across the whole gain for illustration.
Handed identical facts, the two methods differ by $466,000 in assessable income — about $219,000 in tax at the top rate.
Why the gap is so wide
Inflation over the decade ran at about 2.8% a year, totalling 31.8%. The land compounded at 13.3% a year, totalling 250%.
Indexation only ever shelters the inflationary slice of a gain. Where an asset has barely outrun inflation, that slice is most of the gain and indexation is generous. Where an asset has comfortably outrun it, the slice is small and almost everything stays taxable. The 50% discount made no such distinction — it halved everything, real growth included, which is exactly why it suited assets that had grown hard.
There is a clean test. The two methods produce the same answer when growth over the holding period is exactly twice the inflation rate over that period.
Indexation is better only when:
growth < 2 × inflation
Inflation 2015-2025: 31.8%
Breakeven growth: 63.6%
Actual growth: 250%
On a $500,000 purchase, the two methods break even at a sale price of about $818,000. Below that, indexation wins. Above it, the discount does, and the gap widens fast.
What this means across the Wimmera
Land across the Wimmera, the Mallee and much of the western district has not merely kept pace with inflation over the past decade — it has left it well behind, on the back of strong commodity prices, farm consolidation, sustained demand for quality cropping country, tight supply and steady productivity gains.
Any property growing at more than roughly double the inflation rate is one the discount suited better, and for land bought in the 2010s that describes almost the entire district. The picture reverses for assets that have grown slowly — listed shares that have drifted sideways, commercial property in a soft market, a block bought near the peak of a previous cycle. For those, indexation is genuinely the kinder method, and the longer they have been held the more true that becomes. Farming land here has rarely been in that category.
Before any of this matters: the small business concessions
One important caveat. Everything above assumes the gain is fully taxable, and for a great many farming families it is not. Farming land is very often an active asset, and where the basic conditions are met, the small business CGT concessions do far more for a gain of this size than the choice of method ever will.
There are four, and they can be applied in combination:
• The 15-year exemption — where the asset has been held 15 years and the owner is 55 or over and retiring, or permanently incapacitated, the entire gain is disregarded.
• The 50% active asset reduction — halves whatever gain remains.
• The retirement exemption — up to $500,000 over a lifetime disregarded, though amounts must go to superannuation if the owner is under 55.
• The small business rollover — defers the gain where a replacement active asset is acquired.
Access depends on satisfying the basic conditions, principally the $6 million maximum net asset value test or the $2 million aggregated turnover test, along with the active asset test. Land owned by one entity and farmed by a related operating entity can still qualify, which matters given how commonly farms are structured that way.
The practical point is this: a farmer who qualifies for the 15-year exemption is largely indifferent to everything discussed above, because the gain disappears either way. Working out whether the concessions are available should come before working out which method produces the smaller number.
The transitional rules governing how and when the new method takes effect are a subject for another day.
General information only. Not tax, legal or financial advice, and it does not take into account your objectives, financial
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