The composite interest rate increased by two basis points to 0.47% at the end of June, from 0.45% at the end of May.
The Monetary Authority said the rise reflected a moderate increase in the weighted funding cost for deposits.
The composite interest rate is a measure of the average cost of funds of banks.
Data from retail banks, which account for about 90% of the total customers' deposits in the banking sector, are used in the calculation.
