What is Face value?
Face value, also called par value or principal, is the amount a bond's issuer promises to repay when the bond matures. It is also the amount the coupon is calculated on. A bond can trade above or below its face value before maturity, but if the issuer pays in full, the holder at maturity receives the face value.
Why Face value matters
It is the fixed number that the coupon and the repayment are both built on.