By committing to terminate funding if a firm's performance is poor, investors can mitigate managerial incentive problems. These optimal financial constraints, however, encourage rivals to ensure that a firm's performance is poor; this raises the chance that the financial constraints become binding and induce exit. The authors analyze the optimal financial contract in light of this predatory threat. The optimal contract balances the benefits of deterring predation by relaxing financial constraints against the cost of exacerbating incentive problems. Copyright 1990 by American Economic Association.