In West Africa, the Value Added Tax (VAT) policy consists of a uniform tax rate, but several items consumed by rich and poor households, are exempted. We provide an optimal tax framework to reflect on the welfare effects of such a tariff structure, in the context of current debates on domestic...

We study a market with free entry and exit of firms who can produce high-quality output by making a costly but efficient initial unobservable investment. If no learning about this investment occurs, an extreme "lemons problem" develops, no firm invests, and the market shuts down. Learning...