‘Duration’ or Macaulay duration measures the price volatility of fixed income securities. As the term suggests, duration is expressed as a number of years and measures a bond’s sensitivity to change in interest rates. Usually, the higher the duration, the more is the volatility in the prices. To be precise, it measures the change in market value of security due to 1% change in interest rates. In the other words we may explain it as the time an investor would take to get back all his invested money in the bond by way of periodic interest as well as principal repayments in terms of the present value of future payments received from a security/bond.
Duration measure is often used in the comparison of interest rate risk between securities with different coupons and different maturities. It is defined as a measure of how long it takes for the price of a bond to be repaid by the cash flows from it. Bond prices are said to have an inverse relationship with interest rates. The weight of each cash flow is determined by dividing the present value of the cash flow by the price expressed in years. The duration of a fixed income security is always shorter than its term to maturity, except in the case of zero coupon securities where they are the same.
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