Control of a corporation occurs when a single institutional unit owning more than a half of the shares, or equity, of a corporation is able to control its policy and operations by outvoting all other shareholders, if necessary; similarly, a small, organised group of shareholders whose combined ownership of shares exceeds 50 per cent of the total is able to control the corporation by acting in concert; in practice, when ownership of shares is widely diffused among a large number of shareholders, control may be secured by owning 20 per cent or less of the total shares.