This paper examines both leadership choice and welfare consequences of privatisation in an endogenous timing mixed multi‐product oligopoly. It shows that a multi‐product firm undermines the welfare‐maximising efforts of a public firm by cross‐subsidising. The paper demonstrates that a unique subgame perfect Nash equilibrium emerges in a multi‐product market, in contrast to the multiple equilibria of a single‐product market. This unique equilibrium indicates that profit‐maximising private firms retain leadership while a welfare‐maximising public firm acts as a follower. Even on the off‐equilibrium path where the public firm acts as a leader, it rarely generates maximum social welfare. However, privatising the public firm usually harms social welfare and results in a different timing structure in equilibrium.