Grey Market

A grey market or gray market, also known as parallel market, is the trade of a commodity through distribution channels which, while legal, are unofficial, unauthorized, or unintended by the original manufacturer. The term gray economy, however, refers to workers being paid under the table, without paying income taxes or contributing to such public services as Social Security and Medicare. It is sometimes referred to as the underground economy or "hidden economy."

The two main imported manufactured goods that would normally be unavailable or more expensive in a certain country and unissued securities that are not yet traded in official markets. Sometimes the term dark market is used to describe secretive, unregulated (though often technically legal) trading in commodity futures, notably crude oil in 2008. This can be considered a third type of "grey market" since it is legal, yet unregulated, and probably not intended or explicitly authorized by oil producers.