Knowledge that Transforms

[An asymmetric information model of the bid-ask spread is developed for a foreign exchange market subject to occasional government interventions. Traditional tests of the unbiasedness of the forward rate as a predictor of the future spot rate are shown to be inconsistent when the rates are measured as the average of their respective bid and ask quotes. Larger bid-ask spreads on Fridays are documented. Reliable evidence of asymmetric bid-ask spreads for all days of the week, albeit more pronounced on Fridays, are presented. The null hypothesis that the forward rate is an unbiased predictor of the future spot rate continues to be rejected. The regression slope coefficients increase toward unity, however, indicating a less variable risk premium.]

[In this article, we consider the possibility that some liquidity traders preannounce the size of their orders, a practice that has come to be known as "sunshine trading." Two possible effects preannouncement might have on the equilibrium are examined. First, since it identifies certain trades as informationless, preannouncement changes the nature of any informational asymmetries in the market. Second, preannouncement can coordinate the supply and demand of liquidity in the market. We show that preannouncement typically reduces the trading costs of those who preannounce, but its effects on the trading costs and welfare of other traders are ambiguous. We also examine the implications of preannouncement for the distribution of prices and the amount of information that prices reveal.]

[A model of a noncompetitive speculative market is analyzed in which privately informed traders and market makers are risk averse. Market liquidity is found to be nonmonotonic in the number of informed traders, their degree of risk aversion, and the precision of their information. It is also shown that increased liquidity trading leads to reduced price efficiency, and that, under endogenous information acquisition, market liquidity may also be nonmonotonic in the variance of liquidity trades.]

[We survey the variance-bounds tests of asset-price volatility, stressing the econometric aspects of these tests. The first variance-bounds tests of the present-value relation reported apparently striking evidence of excess volatility of asset prices. The statistical significance of the results, however, was either marginal or, in the case of model-free tests, impossible to assess. Moreover, the tests were soon criticized for a number of biases. Various other tests of the present-value relation were later developed, avoiding in different degrees the econometric problems attending the first-generation tests. The majority of these second-generation tests also found excess volatility, though sometimes of borderline statistical significance. This finding of excess volatility is robust and is difficult to explain within the representative-consumer, frictionless-market model.]

[When a security trades at multiple locations simultaneously, an informed trader has several avenues in which to exploit his private information. The greater the proportion of liquidity trading by "large" traders who can split their trades across markets, the larger is the correlation between volume in different markets and the smaller is the informativeness of prices. We show that one of the markets emerges as the dominant location for trading in that security. When informed traders can use their information for more than one trading period, the timely release of price information by market makers at one location adversely affects the profits informed traders expect to make subsequently at other locations. Market makers, competing to offer the lowest cost of trading at their location, consequently deter informed trading by voluntarily making the price information public and by "cracking down" on insider trading.]

[It is demonstrated that markets in stock index futures or, more generally, in baskets of securities, provide a preferred trading medium for uninformed liquidity traders who wish to trade portfolios, because adverse selection costs are typically lower in these markets than in markets for individual securities. Thus, an explanation is provided for the immense liquidity and popularity of markets in stock index futures. Implications are also developed for the effect of the introduction of a basket on market liquidity and the informativeness and variability of component security prices, and for the price relationship between the basket and its underlying portfolio.]

[A simple classical Walrasian framework is proposed for the study of manipulation among asymmetrically informed risk-averse traders in financial markets, and it is used to analyze the occurrence of a market breakdown in the trading system. Such a phenomenon occurs when the outsiders refuse to trade with the insiders because the informational motive for trade of the insider outweighs her hedging motive. We demonstrate the robustness of our results by proving that the market collapse condition extends not only to the linear strategy function, but to the whole class of feasible nonlinear strategy functions. Implications for insider-trading regulation are sketched.]

Changes in stock prices have substantial explanatory power for U.S. investment, especially for long-term samples, and even in the presence of cash flow variables. The stock market dramatically outperforms a standard q-variable because the market-equity component of this variable is only a rough proxy for stock market value. Although the stock market did not predict accurately after the crash of October 1987, the errors were not statistically significant. Parallel relationships for Canada raise the puzzle that Canadian investment appears to react more to the U.S. stock market than to the Canadian market.

Stambaugh, and especially to Robert Merton for comments on a previous draft. This paper is part of NBER's research program in Financial Markets and Monetary Economics. Any opinions expressed are those of the author not those