ABSTRACT This paper examines the price effect of option introduction from 1974 to 1980. The introduction of individual options causes a permanent price increase in the underlying security, beginning approximately three days before introduction. The price effect appears to be associated with introduction, and not announcement, throughout the sample period. Excess returns volatility declines with option introduction. Systematic risk is unchanged. There is a positive relation between the price increase and a measure of activity in the options market.

We examine realized spreads and price impact in clock and trade time following each trade in all common stocks from 2010 to 2017. The term structure of realized spreads (price impact) is sharply downward (upward) sloping, implying that (a) market maker profitability is sensitive to speed, and (b) the choice of the horizon of measurement is critical when drawing inferences from spread decompositions. The majority of the price impact of trades in large (small)-capitalization stocks takes place within 15 (60) seconds. Net profits to liquidity provision, or equivalently, net costs to liquidity demanders, decline over the sample period even at the shortest horizons that we consider: at the 100 ms horizon, aggregate profits decline from 1.9 basis points of total dollar volume in 2010 to 1.0 basis points in 2017.

[In this article we use a single unifying framework to analyze the sources of profits to a wide spectrum of return-based trading strategies implemented in the literature. We show that less than 50% of the 120 strategies implemented in the article yield statistically significant profits and, unconditionally, momentum and contrarian strategies are equally likely to be successful. However, when we condition on the return horizon (short, medium, or long) of the strategy, or the time period during which it is implemented, two patterns emerge. A momentum strategy is usually profitable at the medium (3- to 12-month) horizon, while a contrarian strategy nets statistically significant profits at long horizons, but only during the 1926-1947 subperiod. More importantly, our results show that the cross-sectional variation in the mean returns of individual securities included in these strategies plays an important role in their profitability. The cross-sectional variation can potentially account for the profitability of momentum strategies and it is also responsible for attenuating the profits from price reversals to long-horizon contrarian strategies.]

This article develops and estimates a simple model for monthly expected stock returns that relies on the rapidly decaying structure of shorter-horizon (weekly) expected returns. The most striking aspect of our finds is that the rapid mean reversion in short-horizon expected returns implies much greater variation through time in monthly expected returns than has been documented in earlier studies. For instance, during the 1962 to 1985 period, over 25 percent of the return variance of small firms can be explained by time variation in expected returns.

[This article develops and estimates a simple model for monthly expected stock returns that relies on the rapidly decaying structure of shorter-horizon (weekly) expected returns. The most striking aspect of our findings is that the rapid mean reversion in short-horizon expected returns implies much greater variation through time in monthly expected returns than has been documented in earlier studies. For instance, during the 1962 to 1985 period, over 25 percent of the return variance of small firms can be explained by time variation in expected returns.]

The authors show that the returns to the typical long-term contrarian strategy implemented in previous studies are upwardly biased because they are calculated by cumulating single-per iod (monthly) returns over long intervals. The cumulation process not on ly cumulates "true" returns but also the upward bias in single-period reutrns induced by measurement errors. The authors also show that the remaining "true" returns to loser or winner firms have no relation to overreaction. This study has important implicati ons for event studies that use cumulative returns to assess the impact o f information events.

We examine the relation between high frequency quotation and the behavior of stock prices between 2009 and 2011 for the full cross section of securities in the US. On average, higher quotation activity is associated with price series that more closely resemble a random walk, and significantly lower cost of trading. We also explore market resiliency during periods of exceptionally high low-latency trading: large liquidity drawdowns in which, within the same millisecond, trading algorithms systematically sweep large volume across multiple trading venues. Although such large drawdowns incur trading costs, they do not appear to degrade the price formation process or increase the subsequent cost of trading. In an out-of-sample analysis, we investigate an exogenous technological change to the trading environment on the Tokyo Stock Exchange that dramatically reduces latency and allows co-location of servers. This shock also results in prices more closely resembling a random walk and a sharp decline in the cost of trading.

ABSTRACT This article examines the role of measurement biases, due to order flow effects, in abnormal split ex‐day returns. We conjecture that postsplit orders consist of numerous small buyers and fewer larger sellers. This change in order flow causes closing prices to occur more frequently at the ask price, consistent with Maloney and Mulherin (1992) and Grinblatt and Keim (1991) . In addition, this change causes specialists' spreads to increase, perhaps to offset larger average inventories. We examine both NYSE and NASDAQ samples and find that order flow biases can explain approximately 80 percent (48 percent) of the NYSE (NASDAQ) ex‐day return.