Discount yield is based on the discount calculated using the face value in the denominator. Money market yield and bond equivalent yield are calculated using the holding period yield, which has price (lower value) in the denominator. So the discount yield is lower than all yields when the security is trading at a discount. The money market yield is the holding period yield times 360 / days to maturity and the bond equivalent yield is holding period yield times 365 / days to maturity. So BEY will be higher than the MMY.