I will give a simple example to explain my question. I have looked at ATO website but it is not covered there.
A has 2 parcels of shares 10 @ $1 and 20 @ $2. B acquires A on a 1 for 2 basis. Is the costbase for new B shares 5 @ $2 and 10 @ $4 or simply 15@ $50/15.
I know if the total of B shares are sold , it does not matter but it would if say 5 were.