Mixed Lot Definition
Mixed Lot refers to trading securities that are not a round lot order amount. A round or whole lot is an established trading unit, it usually includes 100 stocks. Orders that fall below the round lot amount, for example 99 shares or less are called "odd" lots. A mixed lot consists of a round lot and an odd lot. If a trader wants to buy 250 shares, a mixed lot order needs to be placed, which is broken into two round lots and an odd lot of 50 shares.