Whether an agreement between horizontal competitors not to compete for certain customers is a per se violation of the Sherman Act, separate from the per se theory of territorial allocation?

QUESTION PRESENTED The Sherman Act treats certain agreements among competitors as illegal per se, without regard to any claimed pro-competitive benefits of the arrangement. These per se violations include price fixing, bid rigging, and horizontal agreements among competitors to divide up markets. Here, the plaintiffs sought to present two separate per se market-division theories to the jury: (1) that the competitor defendants had agreed to allocate territories; and (2) that the defendants had agreed to allocate particular customers. But over the express objection of the plaintiffs, the Court refused to instruct the jury that these theories—if proven—represented separate and independently sufficient per se violations of the Sherman Act. Instead, the district court imposed— and the Eighth Circuit affirmed—a requirement that the plaintiffs prove both a territorial allocation and a customer allocation to establish a per se violation. In doing so, the Eighth Circuit created a disagreement among the courts of appeals over whether a customer allocation agreement is a per se violation separate from any theory of territorial allocation. The question presented is: Whether an agreement between horizontal competitors not to compete for certain customers is a per se violation of the Sherman Act, separate from the per se theory of territorial allocation?