Noncontrolling interest (NCI) is the portion of equity ownership in a subsidiary not attributable to the parent company, who has a controlling interest (greater than 50% but less than 100%) and consolidates the subsidiary's financial results with its own.
For example, suppose company Alpha acquires 80% of the outstanding stock of company Sierra. Because Alpha owns more than 50% of Sierra, Alpha consolidates Sierra's financial results with its own. The 20% of Sierra's equity that Alpha does not own is recorded on Alpha's balance sheet as NCI. Consolidated net income is allocated to the parent and noncontrolling interests (minority shareholders) in proportion to their percentages ownership; 80% to Alpha and 20% to the noncontrolling interests, in this case.