This article includes in an enlarged theory of equilibrium and optimality various government transactions such as production of collective goods, income transfers, direct and indirect taxes. In particular, the link between equilibrium and optimality is analysed in relation to indirect taxation. Considering the assumptions which are adopted, equilibrium does not necessarily imply optimality, but corresponds to a more restrictive concept called "private optimum." Moreover, an optimum is an equilibrium only if special assumptions are made on the nature of choices concerning social welfare goods.