A student asks: If a coupon bond has a face value of $1,000, I dont understand why

Question:

A student asks:
If a coupon bond has a face value of $1,000, I don’t understand why anyone who owns the bond would sell it for less than $1,000. After all, if the owner holds the bond to maturity, the owner knows he or she will receive $1,000, so why sell for less?

Coupon
A coupon or coupon payment is the annual interest rate paid on a bond, expressed as a percentage of the face value and paid from issue date until maturity. Coupons are usually referred to in terms of the coupon rate (the sum of coupons paid in a... Face Value
Face value is a financial term used to describe the nominal or dollar value of a security, as stated by its issuer. For stocks, the face value is the original cost of the stock, as listed on the certificate. For bonds, it is the amount paid to the...