The resurgence of sizable current account imbalances in the major economies in recent years, particularly the tripling of the U.S. deficit, has led to renewed academic and public discussions about their sustainability. Jacob's main objective is to show that current account balances are simply the outcome of various relative structural and cyclical forces between trading partners. He reviews the factors behind the changes in the current account positions of the three largest industrial economies (the United States, Japan, and the euro area). Two strong determinants shaping the current account balances are the faster increase in U.S. productivity compared with that of other major economies and, more recently, the loosening in the U.S. fiscal stance. Jacob also reviews a range of outside assessments from such sources as the Organisation for Economic Co-operation and Development and the International Monetary Fund, as well as the academic literature, to determine the possible risks to macroeconomic and financial stability.