Income tax: capital gains: does the cost base modification in subsection 128-15(4) Item 1 of the Income Tax Assessment Act 1997 apply if a main residence acquired on or after 20 September 1985 is owned by joint tenants and one of them dies?

No. Section 128-50 rather than subsection 128-15(4) Item 1 of the Income Tax Assessment Act 1997 applies.

Section 128-50 applies specifically if a CGT asset is owned by joint tenants and one of them dies. Subsection 128-15(4) provides a general rule which modifies the cost base (or reduced cost base, if applicable) of certain kinds of CGT assets in the hands of a legal personal representative or beneficiary, including an interest in a dwelling that was the main residence of an individual just before they died.

Section 128-50, being a specific provision, applies here rather than subsection 128-15(4) Item 1 which is more generally expressed.

In any event, section 128-15 only applies if a CGT asset owned by the deceased: (a) devolves to their legal personal representative; or (b) passes to a beneficiary in their estate (subsection 128-15(1)).

If joint tenants own a main residence and one of them dies, the surviving joint tenants are taken by subsection 128-50(2) to have acquired the deceased's interest in the main residence. So the interest in the main residence does not: (a) devolve to the deceased's legal personal representative; or (b) pass to a beneficiary in the deceased's estate.

The effect of section 128-50 applying is that the first element of the cost base (indexed if applicable) or reduced cost base of the interest of each surviving joint tenant is a proportion of the cost base of the deceased joint tenant's interest in the main residence (as calculated in subsection 128-50(3)).