The article presents a theoretical survey of different ways to analyze the effect coexistence of spot and forward markets has on incentives for non-competitive behavior. There is no common opinion in economic theory concerning the influence of forward contracts on incentives for non-competitive behavior in spot market. Several studies support the hypothesis that introduction of forward trading increases competition in the spot market by erosion of market power. But while it can reduce market power of an individual firm, forward trading facilitates tacit collusion in the market. This ambiguity demonstrates complexity of economic research, aimed at increasing social welfare.