Русско-англо-русский юридический словарь

A controlling interest is an ownership interest in a corporation with enough voting stock shares to prevail in any stockholders' motion. A majority of voting shares (over 50%) is always a controlling interest. When a party holds less than the majority of the voting shares, other present circumstances can be looked at to determine whether that party is still considered to hold a controlling ownership interest. (Wikipedia)

JD Sports Fashion has taken a controlling interest in Edinburgh-based outdoor clothing and equipment company Tiso Group for an undisclosed sum. (BBC News)

associated company (UK) is a company in which another company has a "significant interest,", that is, a shareholding of 20–50%. An interest of more than 50% is considered a controlling interest (the companies are then parent and subsidiary), while one of less than 20% is considered an investment. In the US the general term is affiliate. (English As a Legal Language by Christine Rossini)

Definition of subholding company: a holding company in which a controlling interest is held by another holding company. (Merriam-Webster Dictionary)