This article provides the crucial definitions of 'Related Parties' and 'Control' that underpin the transfer pricing rules. 'Related Parties' include close relatives (within the fourth degree), an individual and a legal entity with at least 50% ownership or control, and two legal entities under common ownership or control. It also covers partners in a partnership and a person and their Permanent Establishment. 'Control' is defined broadly as the ability to influence another person, including through 50% or more of voting rights, board composition, profit entitlement, or exercising significant influence over business affairs.