A comparison of stock market mechanisms

This paper studies the relationship between the amount of public information that stock market prices incorporate and the equilibrium behavior of market participants. The analysis is framed in a static, NREE setup where traders exchange vectors of assets accessing multidimensional information under two alternative market structures. In the first (the unrestricted system), both informed and uninformed speculators can condition their demands for each traded asset on all equilibrium prices; in the second (the restricted system), they are restricted to condition their demand on the price of the asset they want to trade. I show that informed traders’ incentives to exploit multidimensional private information depend on the number of prices they can condition upon when submitting their demand schedules, and on the specific price formation process one considers. Building on this insight, I then give conditions under which the restricted system is more efficient than the unrestricted system.Financial economics, asset pricing, information and market efficiency

Giffen goods and market making

This paper shows that information effects per se are not responsible for the Giffen goods anomaly affecting competitive traders’ demands in multi- asset, noisy rational expectations equilibrium models. The role that information plays in traders’ strategies also matters. In a market with risk averse, uninformed traders, informed agents have a dual motive for trading: speculation and market making. While speculation entails using prices to assess the effect of private signal error terms, market making requires employing them to disentangle noise traders’ effects in traders’ aggregate orders. In a correlated environment, this complicates a trader’s signal-extraction problem and may generate upward-sloping demand curves. Assuming either (i) that competitive, risk neutral market makers price the assets, or that (ii) the risk tolerance coefficient of uninformed traders grows without bound, removes the market making component from informed traders’ demands, rendering them well behaved in prices.Financial economics, asset pricing, information and market efficiency

Short-term investment and equilibrium multiplicity

I study the effects of the heterogeneity of traders' horizon in the context of a 2-period NREE model where all traders are risk averse. Owing to inventory effects, myopic trading behavior generates multiplicity of equilibria. In particular, two distinct patterns arise. Along the first equilibrium, short term traders anticipate higher second period price reaction to information arrival and, owing to risk aversion, scale back their trading intensity. This, in turn, reduces both risk sharing and information impounding into prices enforcing a high returns' volatility-low price informativeness equilibrium. In the second one, the opposite happens and a low volatility-high price informativeness equilibrium arises.Financial economics, information and market efficiency

A Comparison of Stock Market Mechanism

I analyze a static, noisy rational expectations equilibrium model where traders exchange vectors of assets accessing multi-dimensional information under two alternative market structures. In the first (the unrestricted system), informed speculators condition their demands for each asset on all equilibrium prices and market makers set prices observing all order flows; in the second (the restricted system), speculators are restricted to condition their demand on the price of the asset they want to trade and market makers only observe the order flow of the asset they price. I show that informed traders' incentives to collect and exploit multi-dimensional private information depend on the number of prices they can condition upon when submitting their demand schedules, and on the specific price formation process one considers. Building on this insight, I then give conditions under which the restricted system is more efficient than the unrestricted system.financial economics, asset pricing, information and market efficiency, market mechanisms

Giffen Goods and Market Making

This paper shows that information effects per se are not responsible for the Gi®en goods anomaly affecting competitive traders' demands in multi-asset, noisy rational expectations equilibrium models. The role that information plays in traders' strategies also matters. In a market with risk averse, uninformed traders, informed agents have a dual motive for trading: speculation and market making. While speculation entails using prices to assess the effect of private signal error terms, market making requires employing them to disentangle noise traders' effects in traders' aggregate orders. In a correlated environment, this complicates a trader's signal-extraction problem and may generate upward-sloping demand curves. Assuming either (i) that competitive, risk neutral market makers price the assets, or that (ii) the risk tolerance coefficient of uninformed traders grows without bound, removes the market making component from informed traders' demands, rendering them well behaved in prices.financial economics, asset pricing, information and market efficiency

Insiders-outsiders, transparency and the value of the ticker

We consider a multi-period rational expectations model in which risk-averse investors differ in their information on past transaction prices (the ticker). Some investors (insiders) observe prices in real-time whereas other investors (outsiders) observe prices with a delay. As prices are informative about the asset payoff, insiders get a strictly larger expected utility than outsiders. Yet, information acquisition by one investor exerts a negative externality on other investors. Thus, investors’ average welfare is maximal when access to price information is rationed. We show that a market for price information can implement the fraction of insiders that maximizes investors’ average welfare. This market features a high price to curb excessive acquisition of ticker information. We also show that informational efficiency is greater when the dissemination of ticker information is broader and more timely

Dynamic Trading and Asset Prices: Keynes vs. Hayek

We investigate the dynamics of prices, information and expectations in a competitive, noisy, dynamic asset pricing equilibrium model with long-term investors. We argue that the fact that prices can score worse or better than consensus opinion in predicting the fundamentals is a product of endogenous short-term speculation. For a given, positive level of residual payoff uncertainty, if noise trade displays low persistence rational investors act like market makers, accommodate the order flow, and prices are farther away from fundamentals compared to consensus. This defines a “Keynesian” region; the complementary region is “Hayekian” in that rational investors chase the trend and prices are systematically closer to fundamentals than average expectations. The standard case of no residual uncertainty and noise trading following a random walk is on the frontier of the two regions and identifies the set of deep parameters for which rational investors abide by Keynes’ dictum of concentrating on an asset “long term prospects and those only.” The analysis explains how accommodation and trend chasing strategies differ from momentum and reversal phenomena because of the different information sets that investors and an outside observer have.efficient market hypothesis, long and short-term trading, average expectations, higher order beliefs, over-reliance on public information, opaqueness, momentum, reversal

Expectations, Liquidity, and Short-term Trading

We consider a two-period market with persistent liquidity trading and risk averse privately informed investors who have a one period horizon. With persistence, prices reflect average expectations about fundamentals and liquidity trading. Informed investors engage in “retrospective” learning to reassess the inference about fundamentals made at the early stage of the trading game. This introduces strategic complementarities in the use of information and can yield two stable equilibria which can be ranked in terms of liquidity, volatility, and informational efficiency. We establish the limits of the beauty contest analogy for financial markets and derive a rich set of implications to explain market anomalies, and empirical regularities.price speculation, multiple equilibria, average expectations, public information, momentum and reversal, Beauty Contest

Learning from Prices, Liquidity Spillovers, and Market Segmentation

We describe a new mechanism that explains the transmission of liquidity shocks from one security to another (“liquidity spillovers”). Dealers use prices of other securities as a source of information. As prices of less liquid securities convey less precise information, a drop in liquidity for one security raises the uncertainty for dealers in other securities, thereby affecting their liquidity. The direction of liquidity spillovers is positive if the fraction of dealers with price information on other securities is high enough. Otherwise liquidity spillovers can be negative. For some parameters, the value of price information increases with the number of dealers obtaining this information. In this case, related securities can appear segmented, even if the cost of price information is small.Liquidity spillovers, Liquidity Risk, Contagion, Value of price information, Transparency, Colocation

Higher Order Expectations, Illiquidity, and Short-term Trading

We propose a theory that jointly accounts for an asset illiquidity and for the asset price potential over-reliance on public information. We argue that, when trading frequencies differ across traders, asset prices reflect investors' Higher Order Expectations (HOEs) about the two factors that influence the aggregate demand: fundamentals information and liquidity trades. We show that it is precisely when asset prices are driven by investors' HOEs about fundamentals that they over-rely on public information, the market displays high illiquidity, and low volume of informational trading; conversely, when HOEs about fundamentals are subdued, prices under-rely on public information, the market hovers in a high liquidity state, and the volume of informational trading is high. Over-reliance on public information results from investors' under-reaction to their private signals which, in turn, dampens uncertainty reduction over liquidation prices, favoring an increase in price risk and illiquidity. Therefore, a highly illiquid market implies higher expected returns from contrarian strategies. Equivalently, illiquidity arises as a byproduct of the lack of participation of informed investors in their capacity of liquidity suppliers, a feature that appears to capture some aspects of the recent crisis.Expected returns, multiple equilibria, average expectations, over-reliance on public information, Beauty Contest.