In competition law, market power requirements are often articulated in terms of market shares. The use of market share thresholds, however, conflates two distinct questions: (1) How much market power exists in a given situation? (2) How much market power should the law require? As a consequence,...

There are two very different sources of market power in antitrust cases. The first is traditional market sharebased market power. Market power in antitrust cases also can come from deception, significantly imperfect or asymmetric information, or other types of market failures that usually are...

This paper introduces a novel analysis of the classic quot;persistence of leadershipquot; question, and applies it to a newly constructed dataset for Japanese manufacturing. The analysis rests on an appeal to an empirical quot;scaling relationshipquot; between current market share and the...

We analyze changes in audit fees and market shares of the BIG-4 audit firms (KPMG, PWC, D&T, E&Y) as compared with those of NB-4 (Non-Big 4) auditors in the period 2000-2011. Both relative fees and relative market shares (compared across BIG-4 and NB-4) auditors changed radically over this...