This paper explores the implications of a distinctive feature of the value added tax (VAT) that is stressed by practitioners but essentially ignored by theorists: that it functions, in part, as a tax on the purchases of informal operators from formal sector businesses and, not least, on their imports. It stresses too the potential importance of the creditable withholding taxes that are levied by many developing countries-which have also been ignored. If both of these instruments are optimally deployed, it is shown, then the usual prescription that a small economy should not deploy tariffs rema