This study examines the information asymmetry of the platform economy in the context of the sharing economy. In particular, the focus was placed on Airbnb's superhost policy, and the effects of the platform's reputation badge (quality certification) on transaction volume and moral hazards were analyzed and the effectiveness of various trust-building market-mechanisms was compared. By combining the database of Inside Airbnb and AirDNA, an analysis was conducted of the data on New York City from August 2016 to December 2018 (from Airbnb webpage). Superhost badges have been shown to have a positive impact on performance―providing incentives for hosts to maintain and improve service quality. However, incentive for reputation milking was also found. Indeed, when selected as a superhost, the number of listings increased while service quality and guest satisfaction gradually decreased. This shows the imperfections and limitations of market mechanisms. However, since the moral hazard is not severe, it can be inferred that self-regulation is still effective under a proper design. Besides, the effects of signaling devices were found to differ depending on whether the guest or the host bears the burden of authentication. The results suggest that it is necessary to discuss the optimal design for a trust building mechanism before discussing government intervention in the matter of information asymmetry.

Preface
Executive Summary

Chapter 1 Introduction

Chapter 2 Literature Review: Effects of Reputation Badges

Chapter 3 Information Asymmetry in the Accommodation Sharing Market and Airbnb’s Superhost Policy
　Section 1 Information Asymmetry in the Accommodation Sharing Market
　Section 2 Trust-Building Mechanisms and Airbnb’s Superhost Policy

Chapter 4 Empirical Analysis of Reputation Badge Effects
　Section 1 Data and Basic Analysis
　Section 2 Empirical Analysis of Superhost Badge Effects
　Section 3 Summary

Chapter 5 Conclusion

References
Appendix
ABSTRACT