NYMEX, the acronym for the New York Mercantile Exchange, is the commodity futures exchange that originally provided the market for trading of natural gas futures and options. The NYMEX is now owned and operated by the CME Group of Chicago. Commodities traded on the NYMEX exchange include biofuels, coal, crude oil, electricity, emissions, freight, natural gas, petrochemicals, and refined products. 

In the natural gas industry the term “the NYMEX” is often used to refer to the Henry Hub futures price. 

NYMEX Natural Gas Futures Prices as of November 18, 2021