为什么N不是20

问题如下：

A $1,000 par corporate bond carries a coupon rate of 6%, pays coupons semiannually, and has ten coupon payments remaining to maturity. Market rates are currently 5%. There are 90 days between settlement and the next coupon payment. The dirty and clean prices of the bond, respectively, are closest to:

选项：

A.

$1,043.76, $1,013.76

B.

$1,043.76, $1,028.76

C.

$1,056.73, $1,041.73

D.

$1,069.70, $1,054.70

解释：

The dirty price of the bond 90 days ago is calculated as N = 10, I/Y = 2.5, PMT = 30, FV = 1,000; CPT→PV = 1,043.76. Adjusting the PV for the fact that there are only 90 days until the receipt of the first coupon, then the dirty price now is 1,043.76 × 1.025^(90/180) = 1056.73. Clean price = dirty price – accrued interest = 1056.73 – 30 × (90/180) = 1041.73.