The purchase of a business/ company (the target/ acquiree/ acquired) by another (the acquirer). A privately held company is purchased, in an acquisition, in whole, while an acquirer purchases a publicly traded company by acquiring a controlling interest in it. Acquisitions can take place by means of friendly (friendly takeover) or unfriendly bids (hostile takeover). In the case of unfriendly bids, the target company may fight back with a host of techniques such as shark repellents. Other techniques include unsolicited merger proposals to incumbent management, accumulation of shares in the open market, or proxy fights (aiming  to replace incumbent management with a new one).

An acquisition is also known as a takeover.