The rate of interest, or growth rate, selected by an insurance company. The assumed interest rate is provided to determine the value of an annuity contract and, therefore, the periodic income payment which can be provided to the annuitant. Combined with other factors such as the annuitant's age upon annuitization, spousal coverage options and the type of annuity coverage chosen, the AIR determines the monthly payment the annuitant will receive. |||In other words, the AIR is the minimum interest rate that must be earned on investments in the policyholder's cash-value account in order to cover the insurance company's costs and expected profit margin. A larger AIR will result in a more robust prediction for market returns for the insurance company as well as a greater monthly income payment for the annuitant.