We consider a linear quantity setting duopoly game and analyze which o f t h e players will commit when both players have the possibility t o d o s o . T o that end, we study a 2-stage game in which e a c h player can either commit to a quantity i n stage 1 or wait till stage 2. We s h o w that committing is more risky for the high cost rm and that, consequently, risk dominance considerations, as in Harsanyi and Selten (1988), allow the conclusion that only the low cost rm will choose to commit. Hence, the low cost rm will emerge as the endogenous Stackelberg leader.Hurkens gratefully acknowledges nancial support from EC grant ERBCHGCT 93-0462.