Regulatory authorities set capital requirements to cover the position risk of securities firms and to protect against losses arising from fluctuations in the value of their holdings. The requirements may be set using the comprehensive approach required by the U.S. Securities and Exchange Commission, the building‐block approach required by the European Community, or the portfolio approach required by the United Kingdom. We compare these three alternatives using a large sample of U.K. equity trading books. The portfolio approach systematically specifies larger requirements for riskier books, and vice versa. It is more efficient than the building‐block approach, and far more efficient than the comprehensive approach.

This paper describes an empirical study of over 4000 specific share return forecasts made by 35 UK stockbrokers and by the internal analysts of a large UK investment institution. A comparison of forecast and realised returns reveals a small but potentially useful degree of forecasting ability. A large part of the information content of the forecasts, however, appears to be discounted in the market place within the first month. Nevertheless, an analysis of some 3000 transactions motivated by, and executed at the time of, the forecasts shows that the apparent predictive ability of the recommendations could be translated into superior performance by the fund's investment managers. Differences in forecasting ability between brokers do not appear to persist over time, but predictive accuracy can be improved by pooling simultaneous forecasts from different sources.

This paper examines the problems of estimating risk measures and their stability in thin markets. It shows analytically that conventional approaches used in previous studies can lead to serious overestimates of the stability of risk measures when shares are subject to thin trading. It then demonstrates, using UK data, that this is, in fact, a serious practical problem, and that the resultant biases are of precisely the form predicted. Finally, the paper presents reliable evidence on the stability of UK risk measures by using an estimation method designed to avoid thin trading bias. Using this approach, risk measures are found to be as stable in the UK as they are in the USA.

A central measure of the efficiency of the Initial Public Offering (IPO) market is the extent to which issues are underpriced. We present new and comprehensive evidence covering British IPOs since World War I. During the period from 1917 to 1945, public offers were underpriced by an average of only 3.80%, as compared to 9.15% in the period from 1946 to 1986, and even more after the U.K. stock market was deregulated in 1986. The post‐WWII rise in underpricing cannot be attributed to changes in firm composition, and occurred in spite of improvements in regulation, disclosure, and the prestige of IPO underwriters.