Companies allowed to participate in tender procedures in Bulgaria and in the EU are the ones registered in the country or in any other EU Member State, in third countries which have a special agreement in the field of public procurement with the European Union, or in the countries which have ratified the Multilateral Agreement on Government Procurement concluded within the World Trade Organization. U.S.-based companies can participate only in the cases under the Government Procurement Agreement as contractors in the implementation of individual projects. More information for U.S. companies is available here.