flexiRate interest is based on the Australian Money Market.
The Australian Money Market is comprised of institutions such as banks that lend money to each other for varying periods of time. Australian Money Market rates are based on economic forces such as supply and demand, and they typically rise or fall much more frequently than the Official Cash Rate which is set by the Reserve Bank of Australia.
Generally, the longer the period of time, the higher the interest rate. However this is not always the case.
flexiRates are designed to take advantage of movements in the Australian Money Market, by allowing you to fix the interest rate applying to a portion of your balance for a set period of time. Therefore, the flexiRates on offer may change frequently. However, once you set up a flexiRate, your interest is fixed and guaranteed as long as the nominated period is completed.