We investigate the role that transaction fees play in the bitcoin blockchain's evolution from a mining-based structure to a market-based ecology. We develop a game-theoretic model to explain the factors leading to the emergence of transactions fees, as well as to explain the strategic behavior of miners and users. Our model highlights the role played by mining rewards, transaction fees, price, and waiting time, discusses welfare issues, and examines how microstructure features such as exogenous structural constraints influence the dynamics of user participation on the blockchain. We provide empirical evidence on the model's predictions and discuss implications for bitcoin's evolution.

We investigate the effect of ambiguity about hedge fund investment strategies on asset prices and aggregate welfare. We model some traders (mutual funds) as facing ambiguity about the equilibrium trading strategies of other traders (hedge funds). This ambiguity limits the ability of mutual funds to infer information from prices and has negative effects on market outcomes. We use this analysis to investigate the implications of regulations that affect disclosure requirements of hedge funds or the cost of operating a hedge fund. Our analysis demonstrates how regulations affect asset prices and welfare through their influence on opaque trading.

This paper investigates the informational role of transactions volume in options markets. We develop an asymmetric information model in which informed traders may trade in option or equity markets. We show conditions under which informed traders trade options, and we investigate the implications of this for the linkage between markets. Our model predicts an important informational role for the volume of particular types of option trades. We empirically test our model's hypotheses with intraday option data. Our main empirical result is that negative and positive option volumes contain information about future stock prices.

Using the model structure of Easley and O'Hara (Journal of Finance, 47, 577–604), we demonstrate how the parameters of the market-maker's beliefs can be estimated from trade data. We show how to extract information from both trade and no-trade intervals, and how intraday and interday data provide information. We derive and evaluate tests of model specification and estimate the information content of differential trade sizes. Our work provides a framework for testing extant microstructure models, shows how to extract the information contained in the trading process, and demonstrates the empirical importance of symmetric information models for asset prices.

This paper delineates the link between the existence of information, the timing of trades, and the stochastic process of prices. We show that time affects prices, with the time between trades affecting spreads. Because the absence of trades is correlated with volume, our model predicts a testable relation between spreads and normal and unexpected volume, and demonstrates how volume affects the speed of price adjustment. Our model also demonstrates how the transaction price series will be a biased representation of the true price process, with the variance being both overstated and heteroskedastic.

This paper examines the effects of price-contingent orders on security prices. We show that a market maker who knows the type and composition of trades will set larger spreads and adjust prices faster than if price-contingent orders were not allowed. Because traders have rational expectations over the book, we demonstrate that uncertainty over order type reduces the variance of prices but with a corresponding loss in price informativeness. We also show that the sequence property of price-contingent orders increases the probability of large price movements. This distinction between variance and episodic price volatility has important policy implications.

This paper presents an analysis of the concept of consensus beliefs and its relation to market efficiency. We show that unless traders have rational expectations, the two published interpretations of consensus beliefs are not useful for considerations of market efficiency. One interpretation (see Verrecchia [6] ) has no implication for market efficiency. Under the second interpretation (see Verrecchia [7] , [8] ) consensus beliefs equilibria are efficient, but they typically do not exist unless traders have rational expectations.