Ngân sách lớn hơn có nghĩa lệ phí cao hơn cho các nhà quản lý bên ngoài, và đội ngũ nhân viên nhiều hơn cho các nhà quản lý bên trong. Trong khi chính thức tối ưu hóa bằng cách sử dụng các dữ liệu lịch sử là giá rẻ, nó là một câu hỏi mở cho dù đó là tốt hơn để sử dụng tối ưu hóa để kiểm soát rủi ro, hoặc sử dụng quy tắc truyền thống như tiếp xúc với mục tiêu để ngành công nghiệp | 114 THEORY AND EVIDENCE ON SHORT SELLING favor of a larger budget. The larger budget implies higher fees for outside managers and more staff for inside managers. While formal optimization using historical data is cheap it is an open question whether it is better to use optimization for risk control or to use traditional rules such as target exposure to industries. Multiple Opinions Case The discussion here dealt with the case where there were only two opinions one of which was right and one was wrong. We presumed that we knew which was right a strong assumption . With these assumptions we were able to derive many interesting and useful conclusions. The two opinions case was adequate for developing these conclusions which do hold for more realistic models. However normally there are many different opinions about the value of a security. This situation will be referred to as a divergence of opinion. It is discussed in Chapter CONCLUSIONS Because of restrictions on short selling many overvalued stocks will be excluded from portfolios by being sold if owned or otherwise not bought however they will not be sold short. This is because stocks that promise less than a competitive rate of return should be excluded from portfolios but often are not good short sale candidates especially for those who do not receive use of the proceeds. It follows that prices are set by the most optimistic investors not by the typical investor. In many cases the most optimistic investors are also the over optimistic investors. The result is sometimes overpriced stocks that can be identified by good analysis. Because of the ease of a minority of investors purchasing enough stock to cause it to be overpriced accounting rules should err on the conservative side. Conservatism will seldom lead to underpricing since there will usually be enough well informed investors to keep the stock priced at least competitively. However if the accounting sometimes exaggerates profits there are likely to be
