WMS Gaming, Inc. is a subsidiary of WMS Industries, Inc, which manufactures casino slot machines. The company is credited with the introduction of 5 reel video slot machines to the world-wide market, and WMS Gaming is also known for its manufacture, until 2000, of pinball machines. The company was founded in 1974.

Their corporate office is in Waukegan, Illinois and the primary development campus is in Chicago, Illinois. There are other development, sales and field services office across the United States. The international development offices are in Uxbridge, England and Australia. International Sales is based in Barcelona, Spain. Its fiscal year 2007 revenues were $540 million.[1]

WMS entered the reel-spinning slot machine market in 1994, and in 1996, it introduced its first hit casino slot machine, Reel ‘em In, a "multi-line, multi-coin secondary bonus" video slot machine. It followed this with a number of similar games like Jackpot Party, Boom and Filthy Rich. By 2001, it introduced its Monopoly-themed series of "participation" slots. WMS Gaming holds licenses to manufature gaming machines using the following brands:

• Monopoly
• Men in Black
• Match Game
• Hollywood Squares
• Clint Eastwood
• Powerball
• Green Acres

A common misconception is that WMS is an acronym standing for "Williams Midway Sente". WMS had little connection to Sente, since Bally/Midway closed its Sente division long before WMS acquired it. Williams became WMS in 1987, a year before the acquisition of Midway by WMS was announced. When Williams decided to go public, it needed a shell to cover Williams and any future subsidiaries. As a result, Williams created WMS simply as a shortening of Williams, which it also selected for its NYSE ticker symbol.

http://en.wikipedia.org/wiki/WMS_Gaming