Merger Modernization Act of 1986

Merger Modernization Act of 1986 - Amends the Clayton Act to revise the standard of anticompetitive effects required to prohibit a merger. Prohibits a merger if there is a significant probability that the merger will substantially increase the ability to exercise market power. Defines "the ability to exercise market power" as the ability of one or more firms profitably to maintain prices above competitive levels for a significant period of time.

Directs the courts, in determining whether a merger will substantially increase the ability of a firm to exercise market power, to consider all economic factors relevant to the affected markets, including: (1) the difficulty of entry by foreign or domestic firms into the market; (2) efficiencies derived from the merger; and (3) any other evidence indicating whether the merger will increase the ability to exercise market power.