Addamax

{{Short description|American software company}}

{{More citations needed|date=November 2019}}

{{Use mdy dates|date=May 2024}} {{Use American English|date=May 2024}}

{{Infobox company

| industry = Software

| founded = 1986

| founder = Peter A. Alsberg

| hq_location = Champaign, Illinois

| area_served = Illinois
Maryland

}}

Addamax was an American software company that developed Trusted operating systems based on UNIX System V and Berkeley Software Distribution (BSD) variants of UNIX.{{cite book|last1=Wong|first1=R. M.|title=[1990] Proceedings of the Sixth Annual Computer Security Applications Conference |chapter=A comparison of secure UNIX operating systems |date=1990|pages=322–333 |doi=10.1109/CSAC.1990.143794|publisher=Institute of Electrical and Electronics Engineers|isbn=0-8186-2105-2 |s2cid=21640545 }} The company was founded in 1986 in Champaign, Illinois by Peter A. Alsberg and had a sales and development office in Gaithersburg, Maryland.{{Citation needed|date=January 2020}}

Addamax filed a high-profile antitrust lawsuit in 1991 against the Open Software Foundation (OSF), alleging that OSF created a cartel that controlled the UNIX operating system and exerted monopsony price fixing and led to the company going out of business.{{cite web|url=http://www.gtwassociates.com/answers/Cases/ADDAMAX.htm |title=Addamax Corp. v Open Software Foundation, Digital Equipment Corporation and Hewlett-Packard Company |publisher=GTW |accessdate=March 11, 2012 |url-status=dead |archiveurl=https://web.archive.org/web/20090106122820/http://www.gtwassociates.com/answers/Cases/ADDAMAX.htm |archivedate=January 6, 2009 }}{{cite web |url=http://caselaw.lp.findlaw.com/scripts/getcase.pl?navby=search&case=/data2/circs/1st/971807.html |title=U.S. 1st Circuit Court of Appeals: ADDAMAX CORPORATION v OPEN SOFTWARE |date=September 4, 1998 |work=FindLaw |accessdate=March 11, 2012}}