Are There Regimes of Antitrust Enforcement? An Empirical Analysis

The authors use Hamilton's (1989, 1990) regime-switching technique to estimate a model in which the enforcement index follows a regime-specific AR(1) process. The authors find evidence of long-lived regimes. The high enforcement regime, which lasted from about 1910 to the mid-1960s, produced enforcement that was, on average, almost twice as high as the low enforcement regime. In particular, the Reagan years were not a time of transition to low antitrust enforcement, as is commonly claimed. Rather, the transition to a low enforcement regime had taken place some 15 years earlier.