Image of Porter’s Fiver Forces and complements. In the middle is a circle which reads: Competition (Rivalry amongst firms). Surrounding this circles are four other slightly smaller circles which have the following written in them: Potential or threat of new entrants; Bargaining power of buyers (customers); Bargaining power of suppliers); Threats from substitutes of products or services. Slightly to the side of these is a circle which reads: Complements, goods or services that complement yours.