The New York Mercantile Exchange ( NYMEX ) is the world 's largest physical commodity futures exchange , located in New York City . Its two principal divisions are the New York Mercantile Exchange and the New York Commodities Exchange ( COMEX ) which were once independent companies but are now merged . The company 's two principal divisions are the New York Mercantile Exchange and Commodity Exchange , Inc ( COMEX ) , once separately owned exchanges .