An option (or warrant) with an embedded provision giving the purchaser the right to designate it as either a call or a put for a limited period of time after it is offered. The holder of a call warrant has the right to buy an underlying asset on specific terms, while the holder of a put warrant has the right to sell the asset.

It is also called a call or put (COP), a chooser option, a switchback option, a switchback warrant, or a you-choose warrant.