Online intermediation services can be crucial for the commercial success of undertakings who use such services to reach consumers. To fully exploit the benefits of the online platform economy, it is therefore important that undertakings can trust online intermediation services with which they enter into commercial relationships. This is important mainly because the growing intermediation of transactions through online intermediation services, fuelled by strong data-driven indirect network effects, leads to an increased dependence of such business users, particularly micro, small and medium-sized enterprises (SMEs), on those services in order for them to reach consumers. Given that increasing dependence, the providers of those services often have superior bargaining power, which enables them to, in effect, behave unilaterally in a way that can be unfair and that can be harmful to the legitimate interests of their businesses users and, indirectly, also of consumers in the Union. For instance, they might unilaterally impose on business users practices which grossly deviate from good commercial conduct, or are contrary to good faith and fair dealing. This Regulation addresses such potential frictions in the online platform economy.