This study analyzes the impacts of explicit transaction costs on weak-form market efficiency within the context of the brokerage commission deregulation in Japan in October 1999, which led to lower commission rates across the market. Applying two alternative statistical tests to both daily and...

We investigate the volatility impacts of the full commission deregulation in Japan in October 1999, and find that the deregulation overall tends to significantly increase price volatility in the Japanese equity market, using alternative model specifications and control variables. This finding...