Actuarial Notes

Yield Rate

Study guide: Exam FM-2

The yield rate j (also called the yield to maturity) is the internal rate of return of a bond — the interest rate per period at which the present value of all future cash flows equals the current price P.

P = Fr \cdot a_{\overline{n}|j} + C \cdot v^n

  • F is the face amount, r the coupon rate per period, C the redemption value, n the number of coupons and v = 1/(1+j); the yield rate is the j that solves this equation. Unlike the Coupon Rate r, which is fixed by the bond's terms, the yield rate reflects the bond's market price.
  • A premium bond (P > C) has Fr > Cj — when C = F, as it is unless stated otherwise, the coupon rate exceeds the yield rate; a discount bond (P < C) has Fr < Cj.
  • Bond prices and yields move in opposite directions: if the yield rises, the price falls, and vice versa.
  • The yield rate is the rate actually earned by an investor who buys the bond at P and holds it until redemption.

Finding the Yield Rate A $1{,}000 face value 3-year annual-coupon bond with coupon rate 5\% is currently priced at $950.26. Find its yield rate.

Answer Coupons are Fr = 1{,}000(0.05) = 50 per year and the redemption value is C = 1{,}000, so j solves 50\,a_{\overline{3}|j} + 1{,}000\,v^3 = 950.26 Bracket the root by pricing at two trial rates:

\begin{align*}
P(6.5\%) &= 50(2.64848) + 1{,}000(1.065)^{-3} \\
&= 960.27 \\
P(7\%) &= 50(2.62432) + 1{,}000(1.07)^{-3} \\
&= 947.51
\end{align*}

The price 950.26 lies between them, so interpolate:

\begin{align*}
j &\approx 0.065 + 0.005 \cdot \frac{960.27 - 950.26}{960.27 - 947.51} \\
&= 0.065 + 0.005(0.78448) \\
&= 0.06892
\end{align*}

Solving exactly (BA II Plus: N = 3, PV = 950.26, PMT = -50, FV = -1{,}000, CPT I/Y) gives j = 6.89\%. The bond trades at a discount to its face value because its coupon rate (5\%) is below the yield.