Although markets prevail throughout the world, there are significant differences in the economic, social, political as well as legal institutions in which these markets function. Many of these variations can be attributed in part to differences in levels of economic development and in part to the differing consensus about the role of corporations and of governments in the various countries. The paper compares the models of private market economy and social market economy. An understanding of the rules underlying private market economy and those governing social market economy is important in the context of of the evoloving new global economic architecture.