Something for Option Holders to Consider, page-26

Example: Rights exercised
Assume that, in the previous example, Shanti wanted to acquire more shares in ZAC Ltd. So, she exercises all 500 rights on 1 August 1998 when they were still worth 20 cents each.
There are no CGT consequences arising from Shanti exercising the rights.
However, the 500 shares Shanti acquires on 1 August 1998 when she exercises the rights are subject to CGT and acquired at the time of the exercise.

https://www.ato.gov.au/General/Capi...shares-or-units/Exercising-rights-or-options/