Online advertising and privacy

An online platform auctions an advertising slot. Several advertisers compete in the auction, and consumers differ in their preferences. Prior to the auction, the platform decides whether to allow advertisers to access information about consumers (disclosure) or not (privacy). Disclosure improves the match between advertisers and consumers but increases product prices, even without price‐discrimination. We provide conditions under which disclosure or privacy is privately and/or socially optimal. When advertisers compete on the downstream market, disclosure can lead to an increase or a decrease in product prices depending on the nature of the information.     

Targeted advertising and advertising avoidance

I examine how the increasing ability of firms to target their ads influences market outcomes when consumers have access to advertising‐avoidance tools. Although firms generally benefit from improved targeting, consumers need not. I also show that there may be too little blocking of ads in equilibrium and consider the role of targeted advertising when niche firms compete against mass‐market firms.     

Sequential location games

We study location games where market entry is costly and occurs sequentially, and where consumers are nonuniformly distributed over the unit interval. We show that for certain classes of densities, including monotone and—under some additional restrictions—hump‐shaped and U‐shaped ones, equilibrium locations can be determined independently of when they are occupied. Our analysis reveals a number of peculiarities of the uniform distribution. Extensions of the model allow for price competition and advertisement in media markets, winner‐take‐all competition, trade‐offs between profits in the short and the long run, and firms operating multiple outlets.     

Price‐matching guarantees

Are price‐matching guarantees anticompetitive? We examine the incentives for price‐matching guarantees in markets where information about prices is costly. The conventional explanation of price matching as facilitating cartel pricing finds some theoretical support, but our model provides an additional explanation. A price‐matching guarantee may be a credible and easily understood means of communicating to uninformed consumers that a firm is low priced. The credibility of the signal is assured by the behavior of informed consumers. We contrast the testable implications of our model with those arising from two theories of price matching as anticompetitive, and show that available evidence supports the signalling theory.     

Price competition and reputation in markets for experience goods: an experimental study

We experimentally examine the effects of price competition in markets for experience goods where sellers can build up reputations for quality. We compare price competition to monopolistic markets and markets where prices are exogenously fixed. Although oligopolies benefit consumers regardless of whether prices are fixed or endogenously chosen, we find that price competition lowers efficiency as consumers pay too little attention to reputation for quality. This provides empirical support to recent models in behavioral industrial organization that assume that consumers may, with increasing complexity of the marketplace, focus on selected dimensions of products.     

Reliability and competitive electricity markets

We derive the optimal prices and investment program for an electric power system when there are price‐insensitive retail consumers served by load serving entities that can choose any level of rationing contingent on real‐time prices. We then examine the assumptions required for competitive electricity markets to achieve this optimal price and investment program and the implications of relaxing several of these assumptions. We analyze the interrelationships between regulator‐imposed wholesale market price caps and generating capacity obligations. The implications of potential network collapses for operating reserve requirements and whether market prices yield generation investments consistent with these reserve requirements are examined.     

Financial networks with electronic transactions: modelling,analysis and computations

Abstract

Advances in telecommunication networks, and, in particular, the Internet have transformed the economic landscape for financial decision-making. In this paper, we focus on financial networks with electronic transactions and with different tiers of decision-makers and we develop an integrated framework for the modelling, analysis and computation of solutions to such problems. Specifically, we consider an economy consisting of three types of decision-makers: those with sources of funds; intermediary ones, and consumers associated with the financial products at the demand markets. Those with sources of funds can transact with the intermediaries either physically or electronically as well as directly in an electronic manner with the consumers. The intermediaries, in turn, can also transact with the consumers either in a physical or an electronic fashion. We address the behaviour of the decision-makers, identify the network structure of the problem, derive the equilibrium conditions, and establish the variational inequality formulation. In addition, we propose a continuous time adjustment process for the study of the disequilibrium dynamics and prove that the set of stationary points of the resulting projected dynamical system coincides with the set of solutions of the variational inequality. We then utilize variational inequality theory to derive qualitative properties of the equilibrium price and financial flow pattern. Finally, we apply an algorithm for the determination of equilibrium prices and financial flows in several examples.     

A search cost model of obfuscation

This article develops models in which obfuscation is individually rational for oligopolistic firms. Firms sell a homogeneous good to rational consumers who incur search costs to learn prices. Search costs are endogenized by allowing obfuscation—firms have an unobservable action that increases the time needed to learn their price. One model involves search costs convex in shopping time. We show that slight convexity can dramatically alter the equilibrium price distribution. A second model examines an informational linkage between current and future search costs: consumers are uncertain about a component of search costs. Here, a signal‐jamming mechanism can lead to equilibrium obfuscation.     

信息不对称、过度自信与股价变动

信息传导的非同步和投资者情绪变化是股票市场的两个典型特征,前者会引发投资者之间出现信息不对称问题,后者主要体现为投资者过度自信,两者共同作用影响股票价格变动。本文将信息不对称和投资者过度自信情绪置于同一个分析框架,建立两阶段动态序贯定价理论模型研究现实市场上信息传导过程中股价变动的内在机制。结果表明:(1)面临新信息的进入,投资者对股票收益预期的调整与均衡价格之间具有正相关关系;(2)面临有利消息时,过度自信投资者比例越大,股票的均衡价格越高,投资收益将越低;面临不利消息时则相反;(3)随着过度自信投资者比例以及过度自信程度升高,市场风险溢价将下降;(4)投资者群体在信息传导过程中出现分化,对股价变动形成异质信念,未获取信息和获取信息但未出现过度自信的投资者认为股价被高估,获取信息且出现过度自信的投资者认为价格被低估,促使更多的交易,引发市场成交量和股价变动;(5)过度自信投资者比例与过度自信程度提高均会对市场效率产生正向影响,而对市场深度具有负向效应。最后,基于理论结果对非对称性和持续性等典型的市场波动性特征进行解释。     

Competitive pricing strategies in social networks

We study pricing strategies of competing firms selling heterogeneous products to consumers. Goods are substitutes and there are network externalities between neighboring consumers. In equilibrium, firms price discriminate based on the network positions and charge lower prices to more central consumers. We also show that, under some conditions, firms' equilibrium profits decrease when either the network becomes denser or network effects increase. In contrast, consumers always benefit from being more connected to each other. We determine the optimal network structure and compare uniform pricing and discriminatory pricing from the perspectives of firms and consumers.     

Sales and consumer inventory

Temporary price reductions (sales) are common for many goods and naturally result in a large increase in the quantity sold. We explore whether the data support the hypothesis that these increases are, at least partly, due to demand anticipation: at low prices, consumers store for future consumption. This effect, if present, has broad economic implications. We test the predictions of an inventory model using scanner data with two years of household purchases. The results are consistent with an inventory model and suggest that static demand estimates may overestimate price sensitivity.     

Price discrimination in input markets

We analyze the short‐ and long‐run implications of third‐degree price discrimination in input markets. In contrast to the extant literature, which typically assumes that the supplier is an unconstrained monopolist, in our model input prices are constrained by the threat of demand‐side substitution. In our model, the more efficient buyer receives a discount. A ban on price discrimination thus benefits smaller but hurts more efficient, larger firms. It also stifles incentives to invest and innovate. With linear demand, a ban on price discrimination benefits consumers in the short run but reduces consumer surplus in the long run, which is once again the opposite of what is found without the threat of demand‐side substitution.     

What measure of inflation should a developing country central bank target?

In closed or open economy models with complete markets, targeting core inflation enables monetary policy to maximize welfare by replicating the flexible price equilibrium. We analyze this result in the context of developing economies, where a large proportion of households are credit constrained and the share of food expenditures in total consumption expenditures is high. We develop an open economy model with incomplete financial markets to show that headline inflation targeting improves welfare outcomes. We also compute the optimal price index, which includes a positive weight on food prices but, unlike headline inflation, assigns zero weight to import prices.     

Search,learning, and tracking

In many search markets, some consumers search to learn both the price and their willingness-to-pay whereas others search only to learn prices. When a seller can track indicators of the likelihood that consumers already know their willingness-to-pay, I show that price discrimination reduces profits and welfare relative to uniform pricing if search costs are small, but may increase both if search costs are large. The analysis also applies to sequential search if learning causes the likelihood that consumers know their willingness-to-pay to depend on the search history.     

Strategic price complexity in retail financial markets

There is mounting empirical evidence to suggest that the law of one price is violated in retail financial markets: there is significant price dispersion even when products are homogeneous. Also, despite the large number of firms in the market, prices remain above marginal cost and may even rise as more firms enter. In a non-cooperative oligopoly pricing model, I show that these anomalies arise when firms add complexity to their price structures. Complexity increases the market power of the firms because it prevents some consumers from becoming knowledgeable about prices in the market. In the model, as competition increases, firms tend to add more complexity to their prices as a best response, rather than make their disclosures more transparent. Because this may substantially decrease consumer surplus in these markets, such practices have important welfare implications.     

An Equilibrium Analysis of Hedging with Liquidity Constraints, Speculation, and Government Price Subsidy in a Commodity Market

We develop a simple commodity model to analyze (i) the effects of hedging with liquidity constraints, due to producers' inability to bear unlimited trading losses, (ii) the role of speculation in the process of risk allocation between consumers and producers, and (iii) the equilibrium implications of government price subsidies to the producers. We find that (1) liquidity constraints can cause futures prices to exhibit mean reversion, which then makes speculation profitable; (2) speculation tends to make futures price volatility an increasing function of futures price; and (3) government price subsidy, if actively hedged by the producers, serves to lower the futures risk premium and reduce futures volatility.     

Differentiated networks: equilibrium and efficiency

We consider a model of price competition in a duopoly with product differentiation and network effects. In the efficient allocation, both networks are active and the firm with the highest expected quality has the largest market share. To characterize the equilibrium allocation, we derive necessary and sufficient conditions for uniqueness of the equilibrium of the coordination game played by consumers for given prices. The equilibrium allocation differs from the efficient one for two reasons. First, the equilibrium allocation of consumers to the networks is too balanced, because consumers fail to internalize network externalities. Second, if access to the networks is priced by strategic firms, then the product with the highest expected quality is also the most expensive. This further reduces the asymmetry between market shares and therefore social welfare.     

Imperfect competition and quality signalling

We examine the interplay of imperfect competition and incomplete information in the context of price competition among firms producing horizontally and vertically differentiated substitute products. Incomplete information about vertical quality (consumer satisfaction) signalled via price softens price competition. Low‐quality firms always prefer the incomplete information game to the full‐information analog. Moreover, for “high‐value” markets with a sufficiently high proportion of high‐quality firms, these firms also prefer incomplete information to full information. We find that an increase in the loss to consumers associated with the low‐quality product may perversely benefit low‐quality firms; we consider applications to tort reform and professional licensing.     

Why Do Price Limits Exist in Stock Markets? A Manipulation‐Based Explanation

Numerous stock market regulators around the world impose daily price limits on individual stock price movements. We derive a simple model that shows that price limits may deter stock market manipulators. Based on our model's implications, we predict that regulators impose price limit rules for markets where the likelihood of manipulation is high. We present empirical evidence consistent with this hypothesis. Our study is the first to formally propose a manipulation‐based rationale for the existence of price limits in stock markets.     

Retail electricity competition

We analyze a number of unstudied aspects of retail electricity competition. We first explore the implications of load profiling of consumers whose traditional meters do not permit the measurement of their real‐time consumption. The combination of retail competition and load profiling does not yield the second‐best prices given the non‐price‐responsiveness of retail consumers. We then examine the incentives that electricity retailers have to install each of two types of advanced metering equipment. Finally, we consider the implications of physical limitations on the ability of system operators to cut off individual consumers relying instead on “zonal” rationing of large groups of individual consumers