After initially winning the right to serve the market or the government, firms often cannot foresee future technological changes or market conditions, so the initial contracts between the firms and the government are often incomplete. Renegotiation is often required to improve ex-post efficiency. When the government engages multiple firms, they are still in competition at the renegotiation stage, which yields non-trivial predictions on their interim behavior. We show that ex-post efficiency is achieve by a renegotiation protocol that generalizes the Shapley value, but the ex-post outcome distorts the firms' interim incentive to invest (after signing the initial incomplete contracts and before renegotiation) in surprising ways.