Calculation of the yield of a bond assumes that the cash flows received are reinvested. The additional income from such reinvestment, sometimes called interest-on-interest, depends on the prevailing interest-rate levels at the time of reinvestment, as well as on the reinvestment strategy. Variability in the reinvestment rate of a given strategy because of changes in market interest rates is called reinvestment risk. Reinvestment risk is greater for longer holding periods, as well as for bonds with large, early cash flows, such as high-coupon bonds. It does not exist for zero-coupon bonds that do not amortize.