On 12 September 2023, the Australian Taxation Office (ATO) has published the shortfall interest charge (SIC) rates and general interest charge (GIC) rates for October – December 2023.
How GIC is calculated
Section 8AAD of the Taxation Administration Act 1953 specifies how the rate of the charge is calculated. To work out the daily rate, divide this rate by the number of days in a calendar year.
| Quarter | GIC annual rate | GIC daily rate |
| October – December 2023 | 11.15% | 0.031% |
| July – September 2023 | 10.90% | 0.030% |
How SIC is calculated
SIC is calculated on a daily compounding basis. The formula for calculating SIC is provided in section 280-105 of Schedule 1 to the Taxation Administration Act 1953. It uses a base interest rate and an uplift factor of 3%. The base interest rate is defined in tax legislation and is the 90-day Bank Accepted Bill rate published by the Reserve Bank.
| Quarter | SIC annual rate | SIC daily rate |
| October – December 2023 | 7.15% | 0.020% |
| July – September 2023 | 6.90% | 0.019% |
