为什么要乘2

问题如下：

If the yield to maturity on an annual-pay bond is 7.75%, the bond-equivalent yield is closest to:

选项：

A.8.05%. B.7.90%. C.7.61%.

解释：

C is correct. The bond-equivalent yield = 2 × (1.0775^0.5 – 1) = 0.07605 or 7.61%.

A is incorrect. The bond-equivalent yield is incorrectly calculated as [(1 + 0.0775)² – 1]/2 = 0.0805 or 8.05%.

B is incorrect. The bond-equivalent yield is incorrectly calculated as [1 + (0.0775/2)]² – 1 = 0.079 or 7.90%.

考点：APR的转换

解析：BEY是一年付息两次的等价年收益率。(1+BEY/2)^2=1+APR1，代入可得BEY=7.61%，故选项C正确。