Robust rules for industrial policy in open economics

The theory of strategic trade policy yields ambiguous recommendations for assistance
to exporting firms in oligopolistic industries. However, some writers have suggested that investment subsidies are a more robust recommendation than export subsidies. We show that, though ambiguous in principle, the case for investment subsidies is reasonably robust in practice. Except when functional forms exhibit arbitrary non-linearities, it holds under both Cournot and Bertrand competition, with either cost-reducing or market-expanding investment,
and with or without spillovers. Only if firms have strong asymmetries in their investment behaviour and engage in Bertrand competition is an investment tax clearly justified.