A grant of restricted stock units in which the number of shares granted is linked to stock-price performance. At the maturity date, the number of shares paid out equals the number of MSUs granted multiplied by the ratio of the stock's value at the maturity date to its value at the grant date (subject to some type of cap). Thus you earn more shares if the price rises but fewer if it drops. This is similar to a grant of performance shares with minimum and maximum targets. MSUs are also called market-leveraged units.