Over the past twenty years, antitrust agencies increasingly have used diversion and pricing pressure analyses to help identify which mergers to investigate and then to help identify which mergers to challenge. A key input in these analyses is an estimate of the profits that firms earn on...

Merger retrospectives often use a difference in differences (DID) approach to measure the price effects of mergers. As used in these studies, this approach implicitly assumes that the price in the control market fully controls for supply and demand shocks in the treatment market if the two...

Marathon-Ashland Petroleum's (MAP) 1999 acquisition of the Michigan assets of Ultramar Diamond Shamrock (UDS) increased MAP's share of terminal storage in Michigan from about 16 percent to about 25 percent and increased the share of gasoline stations bearing a MAP brand from about 16 percent to...