Corner

A corner is the act of purchasing enough of a stock, commodity or asset to gain a controlling interest or ownership in order to manipulate the price of that asset.

By buying up a large interest in the security, the cornerer can inflate the price and attempt to force the investors short of the security to cover, thereby causing the price to rise, resulting in a large gain for the cornerer. However, this is illegal and regulators watch market players with significant interests in a security to look for suspicious behavior.