From Wikipedia: To have a "controlling interest" in a corporation means to have control of a block of voting stock shares in a company large enough so that no single stockholder or coalition of stockholders could successfully oppose your motion(s). In theory this normally means that a "controlling interest" would be 50% of the voting shares plus one. In practice, a controlling interest can be far less than that, as it is rare that 100% of a company's voting shareholders actively vote. A company that requires a 2/3 super-majority of shares to vote in favor of a motion can grant 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.