Reinvestment Risk is the risk that an investor may not be able to reinvest cash flows, such as interest payments or principal repayments, at the same rate as the original investment's yield. Reinvestment Risk is the chance of earning less on reinvested funds when interest rates drop. For example, if you receive interest payments from a bond but rates have fallen, you might have to reinvest that money at lower rates, reducing your overall returns. This risk is important for investments like bonds and can be managed by choosing strategies like bond ladders.