accrued-interest-only (AIO): 1. One of the secondary payment streams on the inflation-indexed instruments, which represents the inflationary adjustment on the accrued principal (or RPO strip). 2. One of two payment streams that are stripped from the RPO payment stream, the other being the NPO payment stream. 3. The payment stream that is stripped off and sold to provide a monthly cash payment stream for the present value assets, thereby enhancing their value. 4. The payment stream, along with the RIO payment stream, which the Internal Revenue Service currently deems taxable to taxpayers.