American Society of Mechanical Engineers v. Hydrolevel Corporation, 456 U.S. 556 (1982), is a United States Supreme Court case where a non-profit association, for the first time, was held liable for treble damages under the Sherman Antitrust Act due to antitrust violations.

[2] In 1982 the U.S. Supreme Court held that American Society of Mechanical Engineers (a nonprofit association) was responsible for treble damages under the Sherman Act.

McDonnell and Miller planned to use the response to show that one of their competitors (Hydrolevel Corp) was selling a device not in compliance with the ASME BPV Code.

Subsequently, according to Hydrolevel, it never acquired sufficient market penetration for sustaining business, and eventually went bankrupt.

An appellate court affirmed that ASME was liable because its agents had acted within the scope of their apparent authority.