基于商品质量偏好的双边市场定价策略分析

本文研究了双边市场一方用户群体提供商品或服务的质量在垄断市场情形和单归属（接入）寡头垄断市场情形下对双边市场平台定价问题。研究结果表明：在寡头垄断情形下,消费方和厂商的接入费用和其本身对质量的敏感程度及质量成本系数相关,平台具有鼓励符合条件的用户接入平台的动机。在单归属的寡头垄断情形下,平台之间的厂商无质量差异时,平台倾向于定高价以获取由商品质量引起的双边市场的剩余价值,而消费者和厂商均没有提高商品质量的要求和激励;在寡头平台之间的商品或服务质量差距小,质量信息不透明时,优势平台会随着质量差距扩大而提高厂商的接入费用,其消费者的数量也会增多;若质量信息透明,质量劣势平台为了保持市场份额,其价格与另一寡头平台的消费者市场的接入费用差距与质量差距成正比,而在厂商市场的接入费用差距与质量差距成反比。     

Net Neutrality and internet fragmentation: The role of online advertising

We investigate the relation between Net Neutrality regulation and Internet fragmentation. We model a two-sided market, where Content Providers (CPs) and consumers interact through Internet Service Providers (ISPs), and CPs sell consumers' attention to advertisers. Under Net Neutrality, a zero-price rule is enforced. By contrast, in the Unregulated Regime, ISPs make access to their subscribers for CPs conditional on payment of a termination fee. Multiple impressions of an ad on the same consumer are partially wasteful. Thus, equilibrium ad rates decrease when audiences overlap. We show that ISPs may strategically set termination fees to induce fragmentation. This takes place when advertising revenues are potentially large but strongly diminished by competition among CPs, and when consumers are not highly sensitive to content availability. We therefore identify an important link between termination fees, the online advertising market and Internet fragmentation. We extend the model to account for multi-homing consumers, vertically integrated ISPs, third-party advertising platforms and heterogeneous CPs.     

Seller curation in platforms

This article explores why market platforms do not expel low-quality sellers when screening costs are minimal. I model a platform market with consumer search. The presence of low-quality sellers reduces search intensity, softening competition between sellers and increasing the equilibrium market price. The platform admits some low-quality sellers if competition between sellers is intense. Recommending a high-quality seller and this form of search obfuscation are complementary strategies. The low-quality sellers enable the recommended seller to attract many consumers at a high price and the effect of the recommendation is strengthened as low-quality sellers become more adept at imitating high-quality sellers.     

POSTING MULTIPLE PRICES TO REDUCE THE EFFECTIVENESS OF CONSUMER PRICE SEARCH*

In a model of competition with imperfect consumer price information and incomplete price search, some consumers may end up comparing prices originating from the same supplier: either because one firm sets multiple prices or because a group of firms colludes. This leads to added monopoly power for these firms, and average prices in the mixed strategy equilibrium become higher. There is a shift in welfare from consumers to producers, both with exogenous and endogenous consumer search behaviour. However consumers might search more or less with multiple prices. The implications for the price‐setting equilibrium, competition policy and recent judgements are considered.     

Platform Price Parity Clauses and Consumer Obfuscation*

Several antitrust authorities have investigated platform price parity clauses around the world. I analyze the impact of these clauses when platforms design a search environment for sellers and buyers to interact. In a model where platforms choose the unit search cost faced by consumers, I show when platforms can profitably obfuscate consumers through high search costs. Then, I show that price parity clauses, when exogenously given, can increase or reduce obfuscation, prices, and consumer surplus. Finally, when price parity clauses are endogenous, they are only observed in equilibrium if they hurt consumers.     

Information and two-sided platform profits

We study the effect of different levels of information on two-sided platform profits—under monopoly and competition. One side (developers) is always informed about all prices and therefore forms responsive expectations. In contrast, we allow the other side (users) to be uninformed about prices charged to developers and to hold passive expectations. We show that platforms with more market power (monopoly) prefer facing more informed users. In contrast, platforms with less market power (i.e., facing more intense competition) have the opposite preference: they derive higher profits when users are less informed. The main reason is that price information leads user expectations to be more responsive and therefore amplifies the effect of price reductions. Platforms with more market power benefit because higher responsiveness leads to demand increases, which they are able to capture fully. Competing platforms are affected negatively because more information intensifies price competition.     

Price effects of search advertising restrictions

Some suppliers prohibit their distributors from advertising on search engines if the consumer searches for the supplier's brand name. Such restrictions are referred to as “non-brand bidding agreements” (NBBAs). This paper investigates the effect of NBBAs on retail prices in the Dutch hotel sector, where some hotels impose NBBAs on online hotel booking platforms. An NBBA may protect the hotel's own website against competition from hotels on booking platforms because booking platforms cannot target consumers searching for the hotel with a search ad. This may lead to higher prices on the hotel website. However, an NBBA may also generate ad savings, which may lead to lower prices. We use hotel prices from a meta-search site and data on NBBAs from two hotel booking platforms. To correct for unobserved heterogeneity between hotels with and without NBBA, we apply a trajectory balancing approach within a synthetic difference-in-differences framework. Compared to non-NBBA-hotels, NBBA-hotels charge higher prices on their website relative to the price on booking platforms, suggesting a price increase. We identify cases where it is unlikely that consumers benefit from passed-on ad savings.     

Competitive targeted online advertising

This paper examines how an online publisher utilizes its information about consumer preference to target advertising. In our model, two firms first bid for a prominent ad position in a publisher-organized position auction, and then compete on price in the subsequent product marketplace. We consider two dimensions of consumer heterogeneity. First, consumers are heterogeneous in product preference. Based on their tastes, some consumers prefer one product over the other, whereas other consumers may rank the products in an opposite order. Second, consumers differ in search preference, i.e., “nonshoppers” only consider the advertised product, while “shoppers” always search both firms’ products before buying. We show that targeted advertising based on product preference will mitigate price competition in product markets as well as competition in position auctions, the latter to the detriment of the publisher. In contrast, targeted advertising based on search preference always benefits the publisher, as the winning firm can charge monopoly prices to nonshoppers. We show that the publisher’s optimal choice is to utilize only the information about consumer search preference. We also explore the welfare implications of targeted advertising based on different types of consumer preference.     

Auction Platform Design and the Linkage Principle

This paper examines an auction platform in which the monopoly platform maximizes profits by adjusting participation fees and choosing an auction format. The seller has private information on the quality of the good, and each participating buyer receives a private signal about his valuation of the good. The choice of auction format determines the allocation of trading surplus between the seller and buyers. This paper shows that when the seller's type is affiliated with the buyers' signals, the platform can charge higher participation fees on both sides by choosing a first‐price or descending auction than a second‐price or ascending auction.     

Strategic segmentation of a market

When competing firms target information towards specific consumers through direct marketing activities, complete segmentation of markets can result. We analyze a two-stage duopoly where, prior to price competition, each firm targets information to specific consumers and only consumers informed by a firm can buy from it. This has the effect of endogenously determining market segments in a model of ‘sales'. In equilibrium, pure local monopoly emerges; firms target and sell to mutually exclusive market segments. When the cost of marketing approaches zero, market shares reflect relative production efficiency (equal shares when firms are symmetric); this may not be the case when marketing cost is high.     

Search algorithm,repetitive information,and sales on online platforms

A prominent feature of online sales is that buyers rely on the search tools offered by platforms to process information when searching for products. We develop a model that captures how the search algorithm affects buyers’ search processes, which further influences market equilibrium and welfare. If a platform adopts a highly unequal search algorithm, buyers are likely to obtain repetitive information about a small group of sellers, which causes buyers to consider fewer options and suppresses competition. By using data from food delivery platforms, we provide empirical evidence that markets with less equal distributions of store rankings in search results have higher average prices and more concentrated sales. We suggest that regulators should restrict search algorithms from showing repetitive information.     

Tax-free digital news?

News platforms are struggling. Their printed readership is predominantly old, and their digital product struggles to win the attention of the young. For several decades tax reductions have been used in Europe to increase the circulation of printed newspapers. Would extending these reductions to digital platforms stimulate digital consumption? Using a two-sided pricing model where a print platform and a digital platform compete for multi-homing consumers and advertisers we show that the answer is no. The two-sidedness of the market means that the digital price would increase. Not only would digital circulation decrease but so too would the fraction of consumers that access news from both platforms. Key media policy goals of reach (circulation) and pluralism (multi-homing) would be harmed.     

Quantity competition with access fees

We analyze an oligopoly model where firms choose both quantities and access fees. Per unit prices are determined endogenously to equate quantity demanded with quantity supplied at each firm. In a Nash equilibrium of the game played by firms, the per unit prices equal marginal cost and access fees may or may not extract all consumer surplus. As the number of firms increases, access fees fall below net consumer surplus and toward zero. Existence is guaranteed if Marshallian consumer surplus is not too concave. With open entry, quantity competition with access fees may be less efficient than without access fees.     

Multiproduct two part tariffs

Two part pricing by a multiproduct monopoly and a differentiated oligopoly are examined and compared. Two part pricing policies are seen to depend on whether products are complements or substitutes and on whether or not the market is segmented. A principle result is that although competition tends to lower unit prices, there is no corresponding tendency for competition to reduce entry fees. The unit pricing rule is related to the Ramsey pricing rule. Oligopoly equilibrium unit prices equal marginal cost when there is one consumer type.     

Platform Competition With Cash-Back Rebates Under No Surcharge Rules

We analyze competing strategic platforms setting fees to a local monopolist merchant and cash-back rebates to end users, when the merchant may not surcharge platforms’ customers, a rule imposed by some credit card networks. Each platform has an incentive to gain transactions by increasing the spread between its merchant fee and user rebate above its rival's spread. This incentive yields non-existence of a pure strategy equilibrium in many natural environments. In some circumstances, a mixed strategy equilibrium exists where platforms choose fee structures that induce merchants to accept only one platform with equal probability, a form of monopolistic market allocation.     

Do birds of a feather flock together? Platform’s quality screening and end-users’ choices theory and empirical study of online trading platforms

We propose a model which incorporates both quality and quantity in end-users’ interactions and analyze how platforms can use quality screening to alleviate information asymmetry and motivate end-users’ participations. We address the question from theoretical and empirical perspectives. In the theory, we build a model in which two platforms compete but only one of them screens sellers’ products. We show that the quality screening influences consumers’ expectations of product quality and their choices of sellers and platforms. The resulting screening effect, together with the network and competition effects, further drives sellers to enter different platforms. The equilibrium result indicates that sellers’ incentives to join the platform that screens products follow a non-monotonic relationship with respect to the observable quality of products. We estimate the model in Alibaba’s Platforms - Tmall and Taobao. The results are consistent with the theory. Counterfactual analysis suggests quality screening benefits consumers and Alibaba.     

A Search Model Where Consumers Choose Quantity Based on Expected Price

I describe a price game in which consumers face search costs and base their quantity decision on the expected price. Because of search costs, the choice of the firm they will buy from is described by a random process. I show that the expected equilibrium price is above the monopoly price. This result does not change if demand comes from a small share of perfectly informed consumers with zero search costs.     

Competition reform and household welfare: A microsimulation analysis of the telecommunication sector in Ethiopia

This paper presents a novel simulation method for estimating the likely welfare effects of policy reforms aimed at increasing competition in strategic economic sectors such as mobile phone services. The proposed method relies on a partial equilibrium simulation approach and estimates the welfare impacts on current consumers and the potential welfare effects among new consumers brought into the market by changes in prices due to competition. This approach is applied to the information and communication technology (ICT) sector in Ethiopia, one of the three countries in the world with a monopoly in the market for mobile phone services. Based on household budget survey data for 2015/16 and departing from a baseline reform scenario that dilutes the market share of the state-owned monopoly to 45 percent, the simulation model estimates a 25.3 percent reduction in the price of mobile services and an increase in 5.7 million new users of mobile services. The predicted drop in prices and increased users would generate a combined relative welfare gain of 1.18 percent (1.09 percent among current users and 0.09 percent among new users), that could be translated into a 0.31 percentage point decline in the national poverty rate and equivalent to lifting about 275,000 people out of poverty. Alternative reform scenarios that dilute the market share of the monopoly to 75 percent and to 30 percent are expected to reduce poverty rate in 0.13 and 0.52 percentage points, respectively. The method proposed in this study represents a useful tool for promoting competition reforms in developing countries, particularly in sectors known for excluding significant segments of the population because of high consumer prices.     

Unbundling and infrastructure competition for broadband adoption: Implications for NGA regulation

The common idea of open access policy is that it refers to the sharing of particular elements, such as wholesale access networks, backhaul, under-sea cable and internet exchange points in fixed and mobile networks. In broadband networks, the use of open access policy usually refers to the infrastructure parts, which are considered a bottleneck. Many regulators have generally focused open access policy on fixed broadband networks, especially digital subscriber line (DSL) technology, in the last decade. Local loop unbundling (LLU) regulation is one of the main strategies for the regulator to open access to an incumbent’s bottleneck network in order to soften its monopoly power and encourage competition in the DSL broadband market. The OECD countries have different strategies regarding unbundling local loop and infrastructure competition, as the characteristics and infrastructure networks of countries vary. There are currently more choices of next generation network (NGN) technologies to develop. While local loop unbundling may not be applied fully to NGN development (the cost is not sunk, more technologies are available to implement, incentive of investment by operator), it can indicate benefits and drawbacks of open access policy in the past decade that can be adapted to NGN.The empirical results of this study show that during 2002–2008, LLU regulation was one of the strategies used to increase broadband adoption in countries that had difficulty encouraging infrastructure competition. Unbundling regulation can therefore be implemented carefully and differently in each country that has inefficiency that is harmful to consumers in its market from a monopoly incumbent. Infrastructure competition, on the other hand, is introduced as another strategy to increase broadband adoption. The empirical results of this study indicate that infrastructure competition can be used as a strategy when there are already enough infrastructures in the area or country. These results support the idea of using open access and infrastructure competition policy depending on the existing competition of broadband infrastructure in each country.     

TWO‐SIDED MARKETS WITH PECUNIARY AND PARTICIPATION EXTERNALITIES*

The existing literature on two‐sided markets addresses participation externalities, but it has neglected pecuniary externalities between platforms. In this paper we build a model that incorporates both externalities. In our set‐up, differentiated platforms compete in advertising levels and offer consumers a service free of charge that is financed through advertising. We show that advertising can exhibit the properties of a strategic substitute or complement. Surprisingly, we find that platform profits can increase with market entry and that there are cases in which the level of advertising rises with entry. We also consider endogenous entry and provide a welfare analysis.