FORE Systems, Inc., was a computer network switching equipment company based in Pittsburgh, Pennsylvania.

Founded in 1990 to supply Asynchronous Transfer Mode (ATM) cards for workstation computers, it soon branched out to become a major supplier in the ATM switch market and the extended those product lines to add Internet Protocol switching and other devices.

[2] Francois Bitz, Onat Menzilcioglu, Robert Sansom and Eric Cooper were researchers at Carnegie Mellon University who felt their 1989 project to supply a US Naval Research Laboratories Request for Development had commercial potential.

[3] FORE initially produced Asynchronous Transfer Mode (ATM) network interface cards for Sun Microsystems' SBus and DEC's TURBOchannel based computers in addition to ATM adapters for Silicon Graphics computers.

FORE was acquired by London-based GEC[3] (now Marconi Corporation plc) on 26 April 1999 to complement its Marconi Communications business and to increase its presence in North America, the world's largest telecoms market.

The £2.8bn (US$4.5bn) ($8.4 billion today) price tag for FORE[4] and the £1.3n spent on Reltec a month earlier took a heavy toll on Marconi following the burst of the bubble in 2000/2001.