What began as the Butter and Cheese Exchange in 1872 has evolved to help people invest their bread. NYMEX Holdings' flagship subsidiary, the New York Mercantile Exchange is the world's largest physical commodity futures exchange and a preeminent forum for energy and metals trading. NYMEX ClearPort clears off-exchange trades and sells market data. CME Group, which also owns the Chicago Mercantile Exchange and Chicago Board of Trade, acquired NYMEX in 2008; the partnership between the two firms stretches back to 2006 when the two teamed up to facilitate after-hours trading of energy, platinum, and palladium futures.