ABSTRACTWe study the rivalry between Euronext and the London Stock Exchange (LSE) in the Dutch stock market to test hypotheses about the effect of market fragmentation. As predicted by our theory, the consolidated limit order book is deeper after entry of the LSE. Moreover, cross‐sectionally, we find that a higher trade‐through rate in the entrant market coincides with less liquidity supply in this market. These findings imply that (i) fragmentation of order flow can enhance liquidity supply and (ii) protecting limit orders against trade‐throughs is important.

ABSTRACT Existing research suggests that alternative data are mainly informative about short‐term future outcomes. We show theoretically that the availability of short‐term‐oriented data can induce forecasters to optimally shift their attention from the long term to the short term because it reduces the cost of obtaining short‐term information. Consequently, the informativeness of their long‐term forecasts decreases, even though the informativeness of their short‐term forecasts increases. We test and confirm this prediction by considering how the informativeness of equity analysts' forecasts at various horizons varies over the long run and with their exposure to social media data.

ABSTRACT We compare the optimal trading strategy of an informed speculator when he can trade ahead of incoming news (is “fast”), versus when he cannot (is “slow”). We find that speed matters: the fast speculator's trades account for a larger fraction of trading volume, and are more correlated with short‐run price changes. Nevertheless, he realizes a large fraction of his profits from trading on long‐term price changes. The fast speculator's behavior matches evidence about high‐frequency traders. We predict that stocks with more informative news are more liquid even though they attract more activity from informed high‐frequency traders.

ABSTRACT We show that retail trading activity has a positive effect on the volatility of stock returns, which suggests that retail investors behave as noise traders. To identify this effect, we use a reform of the French stock market that raises the relative cost of speculative trading for retail investors. The daily return volatility of the stocks affected by the reform falls by 20 basis points (a quarter of the sample standard deviation of the return volatility) relative to other stocks. For affected stocks, we also find a significant decrease in the magnitude of return reversals and the price impact of trades.

International audience

We develop a dynamic model of an order-driven market populated by discretionary liquidity traders. These traders must trade, yet can choose the type of order and are fully strategic in their decision. Traders differ by their impatience: less patient traders demand liquidity, more patient traders provide it. Three equilibrium patterns are obtained- the pattern is determined by three parameters: the degree of impatience of the patient traders, which we model as the cost of execution delay in providing liquidity; their proportion in the population, which determines the degree of competition among the liquidity providers; and the tick size, which is the cost of the minimal price improvement. Despite its simplicity, the model generates a rich set of empirical predictions on the relation between market parameters, time to execution, and spreads. We argue that the economic intuition of this model is so basic, its Limit and market orders constitute the core of any order-driven continuous trading

Short-lived arbitrage opportunities arise when prices adjust with a lag to new information. They are toxic because they expose dealers to the risk of trading at stale quotes. Hence, theory implies that more frequent toxic arbitrage opportunities and faster responses to these opportunities should impair liquidity. We provide supporting evidence using data on triangular arbitrage. As predicted, illiquidity is higher on days when the fraction of toxic arbitrage opportunities and arbitrageurs’ relative speed are higher. Overall, our findings suggest that the price efficiency gain of high-frequency arbitrage comes at the cost of increased adverse selection risk. Received March 25, 2015; editorial decision September 21, 2016 by Editor Andrew Karolyi.

Firms significantly reduce their investment in response to nonfundamental drops in the stock price of their product-market peers. We argue that this results stems from managers’ limited ability to filter out the noise in the stock prices when using them as signals about their investment opportunities. Ensuing losses of capital investment and shareholders’ wealth are economically large and even affect firms not facing severe financing constraints or agency problems. Our findings offer a novel perspective on how stock market inefficiencies can affect the real economy, even in the absence of financing or agency frictions.Received December 14, 2016; editorial decision July 30, 2018 by Editor Itay Goldstein. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

ABSTRACT We develop a model in which the speed of reaction to trading opportunities is endogenous. Traders face a trade‐off between the benefit of being first to seize a profit opportunity and the cost of attention required to be first to seize this opportunity. The model provides an explanation for maker/taker pricing, and has implications for the effects of algorithmic trading on liquidity, volume, and welfare. Liquidity suppliers’ and liquidity demanders’ trading intensities reinforce each other, highlighting a new form of liquidity externalities. Data on durations between trades and quotes could be used to identify these externalities.

ABSTRACT We propose a new model of trading in over‐the‐counter markets. Dealers accumulate inventories by trading with end‐investors and trade among each other to reduce their inventory holding costs. Core dealers use a more efficient trading technology than peripheral dealers, who are heterogeneously connected to core dealers and trade with each other bilaterally. Connectedness affects prices and allocations if and only if the peripheral dealers' aggregate inventory position differs from zero. Price dispersion increases in the size of this position. The model generates new predictions about the effects of dealers' connectedness and dealers' aggregate inventories on prices.