Say a property goes up from 400k (purchase price) to 600k (appraisal/valuation) over 4 years. CGT exemption used on a different property over this time. Over the next 4 years, the property goes up from 600k to 700k and then sold. CGT exemption is used on this property for this period. The total capital gain is 700k-400k = 300k. How much of this is exempt from CGT? 100k, since that is the capital gain over the last 4 years 150k, since the exemption was for half of the 8 year ownership period If 1., what happens if no appraisal/valuation is performed? Will the ATO order a backdated market valuation?