A historical method (largely retired post-1999 for individuals) of inflating the cost base by CPI so only real gains are taxed. Proposed for return under the 2027 reform for the post-2027 portion of residential property gains.
Frozen at 30 September 1999 for assets held by individuals at that date. The 2025 Federal Budget proposed reintroducing CPI indexation for the post-1-July-2027 portion of capital gains on residential property - taxing real gains only, but at marginal rate with no 50% discount, subject to the 30% minimum tax floor.