Class Certified in Stock-Drop Case Over Dental-Supply Conspiracy

A group of investors who want to hold dental supplier Patterson Cos. liable for a stock drop following misrepresentations related to antitrust violations was certified as a class by a federal judge in Minnesota.

Patterson is the second-largest distributor of dental supplies in the U.S. and, with its two main competitors, controls nearly 80% of the industry. The companies historically enjoyed large profit margins for acting as middlemen between manufacturers and small dental practices.

Some of these practices consolidated their purchasing power, and the distributors agreed to boycott the groups to eliminate them from the industry. The Federal Trade Commission ...