Illinois Walls: How barring indirect purchaser suits facilitates collusion

In its landmark ruling in Illinois Brick Co. v. Illinois, the U.S. Supreme Court restricted standing to sue for recovery of damages suffered from a breach of federal antitrust law to direct purchasers only. Even though typically antitrust injury is, at least in part, passed on to firms lower in the production chain and ultimately to consumers, Illinois Brick is binding precedent in a majority of states. In this paper, we draw attention to a strategic abuse of the rule as a shield against antitrust damages claims. We show that Illinois Brick facilitates upstream firms in engaging horizontally in a collusive arrangement, allowing them to focus concealed vertical side-payments to discourage civil action on their direct purchasers only. Downstream firms are passed part of the upstream cartel profits through a symmetric rationing of their inputs at low prices. This `Illinois Wall' arrangement sustains collusion in the production chain to the detriment of consumers and reducing total welfare. The more competitive the up- and downstream industries otherwise are, the more scope there is for the arrangement. Illinois Walls are shown to be resilient to entry, as well as to variations in the legal system. Several recent U.S. cartel cases display some of their symptoms, suggesting that the abuse of Illinois Brick is a reality in U.S. industry.