From www.fssuper.com.au: Legislation will make the general interest charge (GIC) and shortfall interest charge (SIC) non-deductible for taxpayers starting from July 1, 2025, impacting those with overdue tax liabilities.

The GIC, set at 11.17% and applied to unpaid tax and superannuation debts, will no longer be deductible, whereas the SIC, set at 7.17%, primarily applies to income tax shortfalls from amended assessments.

Taxpayers should consider timing their assessments and payments to avoid non-deductible charges, as the deductibility will depend on whether the notice of assessment is issued before or after the effective date.