Controlling interest in a corporation means to have control of a large enough block of voting stock shares in a company such that no one stock holder or coalition of stock holders can successfully oppose a motion. In theory this normally means that controlling interest would be 50% of the voting shares plus one.

In practice, though, controlling interest can be far less than that, as it is rare that 100% of a company's voting shareholders actively vote.

In addition, a company that requires a 2/3 super-majority of shares to vote in favor of a motion, can grant, in effect, veto power to a minority shareholder or block of shareholders that own essentially 1/3 of the shares. Thus in some cases, a single entity can essentially maintain control, with only 33.4% of the outstanding shares. Ford Motor Company's ownership of 33.4% of Mazda is an example of a controlling interest with minority shareholding.

Corporate finance | Stock market