Although capital is now generally free to move across national borders, there is strong evidence that savings tend to remain and to be invested in the countiy where the saving takes place. The current paper examines the apparent conflict between the potential mobility of capital and 'the observed de facto segmentation of the global capital market The key to reconciling this "Feldstein-Horioka paradox" is that, although capital is free to move, its owners, and especially the agents who are responsible for institutional investments, prefer to keep funds close to home because of a combination of risk aversion, ignorance and a desire to show prudence in their investing behavior.The paper presents evidence on the capital mobility and on capital market segmentation.The role of hedging and the difference between gross and net capital movements for individual investors and borrowers are discussed. The special place of foreign direct investment is also considered.The segmentation of the global capital market affects the impact of capital income taxes and subsidies. This is discussed in the fmal section of the paper. An occasion like this is a pleasant way of linking one generation to the next within the economics profession. The fifteen recipients of the Harms prize since it was established in 1964 include the man with whom I first studied international economics, Sir Roy Harrod of Oxford, who received the prize in 1966 while I was a graduate student in Oxford. A few years later, the prize went to Wassily Leontief and then to Gottfried Haberler, both of whom were active members of the Harvard Economics department that I had just joined. So it is a special pleasure and indeed a great honor to have been included with these men in the group that the Kiel Institute has honored.As you know, the Harms prize is based on contributions to international economics while my own research over the years has focused on the economics of the public sector, especially the problems of taxation, government spending and social insurance. Most research in public *professor of Economics, Harvard University and President of the National Bureau of Economic Research. These remarks were presented as the Bernhard Harms Prize Lecture on June 24, 1994 in Kid, Germany. I am grateflul to Todd Sinai for help with the statistical estimates presented in section 2 of this paper and to Kathryn Dominguez, Jefiuey Frankel and Kenneth Froot for comments on an earlier draft kiel.082494 economics, including my own, focuses on microeconomic issues: how public policies affect the behavior of households and firms and how to design policies that lead to preferred outcomes.However, much of my own work has been motivated by aggregate national issues like the causes of high unemployment, the impact of inflation, and the determinants and consequences of aggregate capital formation.It was my research on the link between public policies and domestic capital formation that led me to deal with explicitly international issues. About twenty years ago, I began to worry...