Definition of Internet Monopoly Behavior and Measurement of Market Power

Abstract：The monopoly position of Internet giants is the advantage condition for them to gain financial resources，reduce operational cost，and suppress rivals，but it is not beneficial for the overall development of the real economy. To strengthen antitrust and prevent the disorderly expansion of capital，besides strengthening supervision，standard formulation and understanding， institutional construction，the support of related laws，and the effective implementation of administrative supervision are also very important. We should explore the reasons for why we undervalue the Internet competition constraint by combining with Internet service and business pattern，andgives a new interpretation of Internet platform market definition，market power measurement，price- cost relationship and classical anti- trust behaviorswith the consideration of the multilateral nature of the market. From the comprehensive perspective of Internet competition and enforcement，we can see that：the multi-layered nature of Internet service and the multilateral nature of market leads to the undervalued Internet competition constraint，increases the difficulties in Internet anti- trust enforcement and the possibilities of error；the market definition of internet platform and the measurement of market power can dialectically absorb some of the traditional wisdoms，for example，free product anti- trust explores the timely use of product performance testing，profit model testing，and other means to define market boundaries；the positive relationship between price and cost is still valuable in Internet，but should be adjusted；and such classical competitive behaviors as predatory pricing，investment M&A，and behavior coordination are still economically ration in Internet，which should be specifically analyzed according to certain condition. Generally speaking，to accurately implement Internet anti- trust enforcement，we should not only be inclusive and prudent，but also keep pace with the times and update our cognition；and there are no commonly used tools.

Key words：Internet competition；the multilateral nature of market；the multi-layered nature of identity；platform market definition；market power measurement