The new Horizontal Merger Guidelines, if treated by courts as a source of law, would reduce the discretion traditionally exercised by courts in defining relevant markets and market power in merger cases. This is an undesirable shift in the balance of power because courts have used the market power inquiry stage of merger analysis as a general checkpoint or weigh station for evaluating factors relevant to the welfare effects of a merger.
Keith N. Hylton,
Brown Shoe Versus the Horizontal Merger Guidelines
Review of Industrial Organization
Available at: https://doi.org/https://doi-org.ezproxy.bu.edu/10.1007/s11151-011-9311-y