The WET Tax Loophole#
Week 4 — Ad Valorem Design#
Where we left off#
- Week 3: cask wine’s packaging economics, measured
- that was the price before the tax on top of it
- this week: the tax, and what its base is calculated on
- the answer changes which products the structure favours
The outcome is not a drafting oversight. An ad valorem tax taxes value, and the quantity consumers are actually buying is not value. Everything else follows from that sentence.
— Ad Valorem Design and the Wine Equalisation Tax (Australian Tax Policy Journal, 2021)
Learning objectives#
By the end of this lecture you should be able to:
- state the WET base and rate precisely
- calculate WET payable from a wholesale value
- express that tax per standard drink rather than per unit
- explain why the result favours cheap wine specifically
The rule, in full#
29% of wholesale value.
That is the entire mechanism. Not per litre. Not per litre of alcohol. Per dollar of wholesale value.
The consequences are all in the word value — because the thing being bought, measured in week 2’s unit, is not proportional to value.
Two wines, same tax rate#
| Per unit | Cask, 4 L, 10.5% | Bottle, 750 mL, 13.5% |
|---|---|---|
| Wholesale value | $2.00 | $20.00 |
| WET at 29% | $0.58 | $5.80 |
| Standard drinks | 33.1 | 8.0 |
| Tax per standard drink | 1.8c | 72.6c |
The same rate. A forty-fold difference in what the drinker pays in tax to reach the same place.
The rate is identical. The burden is not.#
Why “cheap wine”, not “wine”#
- the tax is proportional to price
- the thing being consumed is proportional to alcohol
- the two are only loosely related, and least related at the bottom of the market
- so the favoured case is not wine in general — it is specifically wine where price per standard drink is already lowest
Week 3 established that cask is exactly that case. The tax compounds the packaging advantage rather than offsetting it.
A structure, not a mistake#
The reading is careful here, and so should you be:
- the tax does exactly what an ad valorem tax does
- nobody drafted it to produce this outcome, and nobody drafted it to avoid the outcome either
- the effect is invisible at the stated rate and only appears once week 2’s metric is applied to outcomes
- calling it a loophole describes the result, not an intent
Common errors#
- applying 29% to the retail price rather than the wholesale value
- comparing tax per bottle instead of tax per standard drink, which reverses the conclusion
- assuming a higher tax bill means a heavier tax burden
- treating the inversion as evidence of bad faith rather than of base choice
Where this connects#
- week 6 examines the opposite design, and what it costs to close this gap
- the WET Policy Brief wants one specific, evidenced claim of exactly this shape, from your own catalogue
- the week 4 lab has you find the inversion point in your own data
Next week#
Elasticity: why the most heavily discounted category in the shop is the one that responds hardest to being discounted.