A slang phrase used to describe a firm who has become a potential takeover target or has put itself up for sale. once a bid is made, a company is put "in play" and will often attract additional bidders.

When a firm becomes a potential takeover target, its share price will typically increase on the expectations of being bought out. For example, in the late 1980s, management at RJR Nabisco felt the share price was unjustifiably low, so it made a bid to take the company private. This bid put the company in play, soliciting numerous other bids, sending RJR Nabisco's share price through the roof.