Global turnover in foreign exchange markets averaged $1.2 trillion per day according to the most recent estimates available from the Bank for International Settlements. 1 Yet, cross-border trade of goods and services accounts for less than 5 percent of the total trading. While it is difficult to get precise estimates on hedging, roughly 20 percent of total trading is aimed at hedging against future exchange rate changes. The remaining roughly 75 percent of total turnover in global foreign exchange markets is believed to be related to short or long term exchange rate speculation. The large fraction of global turnover in currency markets that is unrelated to trade or hedging has lead economists and policy markets to the conjecture that speculation is responsible for the perceived recent increase in volatility in foreign exchange markets. Several economists, most prominently Nobel Laureate Dr. James Tobin, have advocated levying a tax (a "Tobin tax") on foreign exchange transactions to reduce volatility induced by exchange rate speculation. Recently, several European countries spearheaded by France have debated a proposed legislation to impose a tax on currency transactions. 2 However, to date, there is no strong empirical evidence that an increase in transactions costs (which would be the result of a Tobin tax) would significantly dampen volatility. On the contrary, This is the first piece of legislation in the world that would implement a Tobin-type tax. Belgium passed similar legislation in March, 2002, and several other European Union member countries have debated a Tobin tax. See www.currencytax.org.

The strength of economic theory is that it can look at the hypothetical rather than merely ex-post rationalize observed behavior. In particular, it can ask the 'what if' question of how changes in model parameters might affect efficiency and social welfare. Based on the answer, it can then suggest welfare-improving policy measures in situations in which privately optimal outcomes are socially inefficient.

Statement of Financial Accounting Standards No. 109 (SFAS No. 109) allows firms to use their discretion to set arbitrarily high valuation allowances against deferred tax assets. Firms can then later use these "hidden reserves" to manage earnings. Our evidence indicates that most banks do not record a valuation allowance to manage earnings, but rather to follow the guidelines of SFAS No. 109. However, if the bank is sufficiently well capitalized to absorb the current‐period impact on capital, then the amount of the valuation allowance increases with a bank's capital. In later years, bank managers adjust the valuation allowance to smooth earnings. The magnitude of the discretionary adjustment increases with the deviation of unadjusted earnings from the forecast or historical earnings.

This paper presents evidence of anomalies in internet firms’ stock returns surrounding their quarterly earnings announcements. There is a general runup in prices in the days prior to the earnings announcements, followed by a price reversal lasting for several days. The magnitude of the market-adjusted returns associated with these price movements exceeds 11 percent over a 10-day period. We find little evidence to suggest that these returns can be explained either by the earnings news disclosed or by risk changes. Additional analyses suggest that these return patterns are driven, at least in part, by price pressure.

We develop an approximate solution method for the optimal consumption and portfolio choice problem of an infinitely long-lived investor with Epstein–Zin utility who faces a set of asset returns described by a vector autoregression in returns and state variables. Empirical estimates in long-run annual and post-war quarterly U.S. data suggest that the predictability of stock returns greatly increases the optimal demand for stocks. The role of nominal bonds in long-term portfolios depends on the importance of real interest rate risk relative to other sources of risk. Long-term inflation-indexed bonds greatly increase the utility of conservative investors.

Between 1984 and 2001, the share of nonelderly adults receiving Social Security Disability Insurance income (DI) rose by 60 percent to 5.3 million beneficiaries. Rapid program growth despite improving aggregate health appears to be explained by reduced screening stringency, declining demand for less skilled workers, and an unforeseen increase in the earnings replacement rate. We estimate that the sum of these forces doubled the labor force exit propensity of displaced high school dropouts after 1984, lowering measured U. S. unemployment by one-half a percentage point. Steady state calculations augur a further 40 percent increase in the rate of DI receipt.

We propose a boundedly rational model of opinion formation in which individuals are subject to persuasion bias; that is, they fail to account for possible repetition in the information they receive. We show that persuasion bias implies the phenomenon of social influence, whereby one's influence on group opinions depends not only on accuracy, but also on how well-connected one is in the social network that determines communication. Persuasion bias also implies the phenomenon of unidimensional opinions; that is, individuals' opinions over a multidimensional set of issues converge to a single “left-right” spectrum. We explore the implications of our model in several natural settings, including political science and marketing, and we obtain a number of novel empirical implications.

People exaggerate the degree to which their future tastes will resemble their current tastes. We present evidence from a variety of domains which demonstrates the prevalence of such projection bias, develop a formal model of it, and use this model to demonstrate its importance in economic environments. We show that, when people exhibit habit formation, projection bias leads people to consume too much early in life, and to decide, as time passes, to consume more—and save less—than originally planned. Projection bias can also lead to misguided purchases of durable goods. We discuss a number of additional applications and implications.