In recent years the field of finance has exploded with innovation. New products, services and techniques abound. The risks of inflation, the volatility of interest rates, the deregulation of financial intermediaries and the unbundling of financial services have combined to present investment managers with challenges and opportunities far greater than in the past. For trustees and managers of pension, trust, endowment, and similar funds, the task of meeting the challenges and exploiting the opportunities is much more difficult. These fiduciaries must measure their investment decisions against constrained interpretations of a legal standard—the prudent man rule—that have caused it to lag far behind changes in investment theory and the marketplace. Drawing on financial history, a major opinion survey of institutional investors, and comprehensive reviews of the law and of the lessons of modern portfolio theory for prudence, this book presents a powerful case that the prudent man rule as elaborated in legal treatises and much of the case law would virtually compel a fiduciary to act imprudently in terms of financial theory and marketplace reality. In proposing a modern paradigm of investment prudence, the book uses illustrations drawn from such traditionally suspect categories of investment fiduciaries as securities lending, real estate, venture capital, options and futures and repurchaser agreements. An unusual examination of the interaction of the worlds of law and finance, this work will be of interest to fiduciaries who are subject to some from of prudent man rule and all others, including judges, lawyers and investment managers, who are called upon to interpret and apply that legal standard.