The present paper surveys and critically evaluates merger policies in the European union. This is done on the basis of economic theory, or rather: theories, since expert opinions on merger policies differ widely. Comparisons are being made with merger cases and policies in the United States. Albeit not a benchmark, US antitrust legislation and practice boast a long history, have been influenced by theoretical arguments put forward by academic circles and, last but not least they were a source of inspiration at the conception of European policy making in the area. Findings indicate that the outstanding feature not only of competition policy but also of the theoretical analysis on which it is based is their highly political character, and that there is as yet no hard empirical evidence to indicate what microeconomic policies would yield the optimal outcome.