Recent press accounts claim that collusion is common practice in Treasury auctions and that as a result the auction profits are excessive. But, this paper finds that the auction prices are on average marginally higher than the secondary market bid prices. The auction profits, however, are systematically related to the total fraction of winning bids tendered by banks and dealers. The postauction prices of the two‐year notes in which Salomon Brothers had a 94 percent holding are also examined. The secondary market prices of these notes were significantly higher than the estimated competitive prices in the four‐week postissue period.

Recent press accounts claim that collusion is common practice in Treasury auctions and that as a result the auction profits are excessive. But, this paper finds that the auction prices are on average marginally higher than the secondary market bid prices. The auction profits, however, are systematically related to the total fraction of winning bids tendered by banks and dealers. The postauction prices of the two-year notes in which Salomon Brothers had a 94 percent holding are also examined. The secondary market prices of these notes were significantly higher than the estimated competitive prices in the four-week postissue period.

The evidence of slowly mean-reverting components in stock prices has been controversial. The hypothesis of stock price mean-reversion is tested using a regression model that yields the highest asymptotic power among a class of regression tests. Although the evidence that the equally weighted index of stocks exhibits mean-reversion is significant in the period 1926–1988, this phenomenon is entirely concentrated in January. In the post-war period both the equally weighted and the value-weighted indices exhibit seasonal mean-reversion in January. A similar phenomenon is also observed for the equally weighted index of stocks traded on the London Stock Exchange.

The evidence of slowly mean-reverting components in stock prices has been controversial. The hypothesis of stock price mean-reversion is tested using a regression model that yields the highest asymptotic power among a class of regression tests. Although the evidence that the equally weighted index of stocks exhibits mean-reversion is significant in the period 1926-88, this phenomenon is entirely concentrated in January. In the postwar period, both the equally weighted and the value-weighted indices exhibit seasonal mean-reversion in January. A similar phenomenon is also observed for the equally weighted index of stocks traded on the London Stock Exchange.

The evidence of slowly mean‐reverting components in stock prices has been controversial. The hypothesis of stock price mean‐reversion is tested using a regression model that yields the highest asymptotic power among a class of regression tests. Although the evidence that the equally weighted index of stocks exhibits mean‐reversion is significant in the period 1926–1988, this phenomenon is entirely concentrated in January. In the post‐war period both the equally weighted and the value‐weighted indices exhibit seasonal mean‐reversion in January. A similar phenomenon is also observed for the equally weighted index of stocks traded on the London Stock Exchange.

This paper presents new empirical evidence of predictability of individual stock returns. The negative first-order serial correlation in monthly stock returns is highly significant. Furthermore, significant positive serial correlation is found at longer lags, and the twelve-month serial correlation is particularly strong. Using the observed systematic behavior of stock returns, one-step-ahead return forecasts are made and ten portfolios are formed from the forecasts. The difference between the abnormal returns on the extreme decile portfolios over the period 1934–1987 is 2.49 percent per month.

This paper presents new empirical evidence of predictability of individual stock returns. The negative first-order serial correlation in monthly stock returns is highly significant. Furthermore, significant positive serial correlation is found at longer lags, and the twelve-month serial correlation is particularly strong. Using the observed systematic behavior of stock return, one-step-ahead return forecasts are made and ten portfolios are formed from the forecasts. The difference between the abnormal returns on the extreme decile portfolios over the period 1934-87 is 2.49 percent per month.

This paper presents new empirical evidence of predictability of individual stock returns. The negative first‐order serial correlation in monthly stock returns is highly significant. Furthermore, significant positive serial correlation is found at longer lags, and the twelve‐month serial correlation is particularly strong. Using the observed systematic behavior of stock returns, one‐step‐ahead return forecasts are made and ten portfolios are formed from the forecasts. The difference between the abnormal returns on the extreme decile portfolios over the period 1934–1987 is 2.49 percent per month .