| Randy Stutz, David O. Fisher
Section 1 of the Sherman Act, Price Fixing
On May 26, 2026, the American Antitrust Institute (AAI) filed an amicus brief in In re Libor-Based Financial Instruments Antitrust Litigation, No. 25-2756, asking the Second Circuit to reverse a district court’s opinion granting summary judgment to defendant banks in investors’ Section 1 claim arising out of the London Interbank Offered Rate (LIBOR) bid-rigging scandal uncovered in the wake of the 2008 financial crisis.
The plaintiffs, a large group of investors, brought Section 1 claims against 16 major banks for conspiring to manipulate the U.S. dollar LIBOR to depress interest payments and improve public perceptions of their financial health between 2007 and 2010. In 2016, after the district court dismissed the case for failing to allege antitrust injury, the Second Circuit reversed, relying on arguments presented in an AAI amicus brief to hold that the plaintiffs properly alleged horizontal price fixing and antitrust injury.
In 2025, after discovery, the district court granted summary judgment for the defendant banks, reasoning that, because the record contained no direct evidence, the plaintiffs had to show parallel conduct and “plus factors” establishing the existence of an illegal conspiracy. The court held that their evidence failed to rule out the possibility that the banks acted unilaterally, without conspiring.
AAI’s brief argues that the district court was wrong to force the plaintiffs’ claims into the so-called parallel-plus framework and that, in addition, it misapplied the standard for assessing parallel conduct within that framework. To prove their Section 1 claim, the plaintiffs relied on both economic evidence of the banks’ parallel offering-rate submissions and non-economic evidence of verbal communications that independently supported an inference that the banks coordinated their submissions. The district court held that the written communications, because they did not qualify as direct evidence of an agreement, were ambiguous and therefore lacked probative value under Matsushita. It further held that, because the plaintiffs relied only on circumstantial evidence, they could prove a Section 1 claim only using the parallel-plus framework.
The AAI brief explains that evidence similar to the evidence in this case has been deemed direct evidence by other courts, and even if the evidence is circumstantial, it is not rendered ambiguous or insufficient under Matsushita simply because it is subject to competing inferences. The distinction between direct and circumstantial evidence is often illusory and does not support a legal rule that formulaically forces parties into alternative modes of analysis.
AAI also argued that Section 1 plaintiffs can independently prove their claims outside the parallel-plus framework by relying on non-economic evidence of an actual agreement, and under the summary judgment standard, courts may not take the case from a jury if a reasonable juror could draw one of multiple competing inferences in the plaintiffs’ favor.
AAI also explained that, even under the parallel-plus framework, the plaintiffs’ cumulative evidence should have been more than enough to establish parallel conduct, and the district court failed to follow the Second Circuit’s guidance on examining plus factor evidence holistically.
The brief was written by AAI President Randy Stutz and AAI Senior Counsel David O. Fisher.
Read the full brief: AAI’s Amicus Brief (In re Libor-Based Financial Instruments Antitrust Litigation
