This paper tests the tax explanation of the January effect by examining small firm stock returns before the War Revenue Act of 1917. No evidence of a turn‐of‐the‐year effect is found. This paper also extends previous authors' work on the subject to 1918–29. A January effect is found during that period.

We develop a bid‐ask spread estimator from daily high and low prices. Daily high (low) prices are almost always buy (sell) trades. Hence, the high–low ratio reflects both the stock's variance and its bid‐ask spread. Although the variance component of the high–low ratio is proportional to the return interval, the spread component is not. This allows us to derive a spread estimator as a function of high–low ratios over 1‐day and 2‐day intervals. The estimator is easy to calculate, can be applied in a variety of research areas, and generally outperforms other low‐frequency estimators.

We examine syndicates for 1,638 IPOs from January 1997 through June 2002. We find strong evidence of information production by syndicate members. Offer prices are more likely to be revised in response to information when the syndicate has more underwriters and especially more co‐managers. More co‐managers also result in more analyst coverage and additional market makers following the IPO. Relationships between underwriters are critical in determining the composition of syndicates, perhaps because they mitigate free‐riding and moral hazard problems. While there appear to be benefits to larger syndicates, we discuss several factors that may limit syndicate size.

On May 26 and 27, 1994, several national newspapers reported the findings of W. Christie and P. Schultz (1994) who cannot reject the hypothesis that marketmakers of active NASDAQ stocks implicitly colluded to maintain spreads of at least $0.25 by avoiding odd-eighth quotes. On May 27, dealers in Amgen, Cisco Systems, and Microsoft sharply increased their use of odd-eighth quotes, and mean inside and effective spreads fell nearly 50 percent. This pattern was repeated for Apple Computer the following trading day. Using individual dealer quotes for Apple and Microsoft, the authors find that virtually all dealers moved in unison to adopt odd-eighth quotes.

We examine 47 stocks that voluntarily left the American Stock Exchange from 1992 through 1995 and listed on the Nasdaq. We find that both effective and quoted spreads increase by about 100 percent after listing on the Nasdaq. These spread changes are consistent across stocks. In contrast, excess returns are positive when firms announce a switch from The American Stock Exchange to the Nasdaq. We are unable to explain this apparent contradiction.

We examine 47 stocks that voluntarily left the American Stock Exchange from 1992 through 1995 and listed on the Nasdaq. We find that both effective and quoted spreads increase by about 100 percent after listing on the Nasdaq. These spread changes are consistent across stocks. In contrast, excess returns are positive when firms announce a switch from The American Stock Exchange to the Nasdaq. We are unable to explain this apparent contradiction.

The NASDAQ multiple dealer market is designed to produce narrow bid‐ask spreads through the competition for order flow among individual dealers. However, we find that odd‐eighth quotes are virtually nonexistent for 70 of 100 actively traded NASDAQ securities, including Apple Computer and Lotus Development. The lack of odd‐eighth quotes cannot be explained by the negotiation hypothesis of Harris (1991) , trading activity, or other variables thought to impact spreads. This result implies that the inside spread for a large number of NASDAQ stocks is at least $0.25 and raises the question of whether NASDAQ dealers implicitly collude to maintain wide spreads.

We examine how the September 2008 short sale restrictions and the accompanying confusion and regulatory uncertainty impacted equity option markets. We find that the short sale ban is associated with dramatically increased bid‐ask spreads for options on banned stocks. In addition, synthetic share prices for banned stocks become significantly lower than actual share prices during the ban. We find similar results for synthetic share prices of hard‐to‐borrow stocks, suggesting that the dislocation in actual and synthetic share prices is attributable to the increased hedging costs for options on banned stocks during the short sale ban.

Many believe that a bubble existed in Internet stocks in the 1999 to 2000 period, and that short‐sale restrictions prevented rational investors from driving Internet stock prices to reasonable levels. In the presence of such short‐sale constraints, option and stock prices could decouple during a bubble. Using intraday options data from the peak of the Internet bubble, we find almost no evidence that synthetic stock prices diverged from actual stock prices. We also show that the general public could cheaply short synthetically using options. In summary, we find no evidence that short‐sale restrictions affected Internet stock prices.