Money Market Yield

The CFAI books give two definitions of the money market yield. In Quant its: r = 360® / [360 - (t)®] In Corp Fin its: MMY = [(Face value - Purchase price) / Purchase price] * (360/t) Anyone either know why there’s two different definitions or when to use which? Thanks,

MMY = HPY X 360 /T or 360 X RBD/ 360 - TXR

Meazza I thought your first definition of MMY is the definition for EAY (effective annual yield)?

No EAY = (1 + HPY)^365/t -1

Nevermind 360/t is the exponent to 1 + HPY for the EAY geeze

Alright got ya, thanks