This article demonstrates that significant net efficiencies from a merger could cause prices to decrease, even if the merger results in a monopoly. The article also shows that a price focus would require substantially more efficiencies to justify an otherwise anticompetitive merger than would an efficiency focus (in other words, it re-does the Williamsonian merger tradeoff, using price to consumers instead of net efficiencies as its focus). We demonstrate this by calculating how large the necessary efficiency gains would have to be to prevent price increases under different market conditions.
Afterword: Could a Merger Lead to Both a Monopoly and a Lower Price?, 71 Cal. L. Rev. 1697 (1983)