Addamax is an American software company founded in 1986 in Champaign, Illinois by Dr. Peter A. Alsberg. They developed Trusted operating systems based on ATT System V and Berkeley (BSD) variants of UNIX. The company had a sales and development office in Gaithersburg, Maryland.
Addamax filed a high profile anti-trust lawsuit in 1991 against the Open Software Foundation also known as OSF, alleging that OSF created a cartel that controlled the UNIX operating system and exerted monopsony price fixing.