The Department of Justice warned a group of gastroenterologists in eastern Pennsylvania who wanted to merge their practices that it may take action against the merger. The twelve doctors noted that there were 21 other gastroenterologists in the Greater Lehigh Valley. But Joel Klein, acting assistant attorney general of the Justice Department's Antitrust Division, cited the Lehigh River as an insurmountable "psychological barrier," thus restricting the observed market to include only Allentown and boosting their supposed share of that market to 92 percent.

Previously, the Federal Trade Commission had blocked the proposed merger between Staples and Office Depot, even though the new office supply superstore would only constitute six percent of the market.

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