I address the controversy over whether the financial services industry is "too big." We should be asking whether the finance industry is functioning properly instead. The facts suggest that demand for financial services increased, perhaps temporarily, rather than suggesting a changing distortion...

Mean-variance portfolio theory can apply to the streams of payoffs such as dividends following an initial investment, in place of one-period returns. This description is especially useful when returns are not independent over time and investors have non-marketed income. Investors hedge their...

In standard solutions, the new-Keynesian model produces a deep recession with deflation in a liquidity trap. The model also makes unusual policy predictions: Useless government spending, technical regress, and capital destruction have large multipliers. These predictions become larger as prices...

I analyze monetary policy with interest on reserves and a large balance sheet. I show that conventional theories do not determine inflation in this regime, so I base the analysis on the fiscal theory of the price level. I find that monetary policy can peg the nominal rate, and determine expected...

Financial innovation challenges the foundations of monetary theory, and standard monetary theory has not been very successful at describing the history of U.S. inflation. Motivated by these observations, I ask: Can we understand the history of U.S. inflation using a framework that ignores...

Bennett McCallum (2009), applying Evans and Honkapohja's (2001) results, argues that "learnability" can save New-Keynesian models from their indeterminacies. He claims the unique bounded equilibrium is learnable, and the explosive equilibria are not. However, he assumes that agents can directly...

I use the valuation equation of government debt to understand fiscal and monetary policy in and following the great recession of 2008-2009, to think about fiscal pressures on US inflation, and what sequence of events might surround such an inflation. I emphasize that a fiscal inflation can come...

I translate familiar concepts of discrete-time time-series to contnuous-time equivalent. I cover lag operators, ARMA models, the relation between levels and differences, integration and cointegration, and the Hansen-Sargent prediction formulas.

It is often useful to price assets and other random payoffs by reference to other observed prices rather than construct full-fledged economic asset pricing models. This approach breaks down if one cannot find a perfect replicating portfolio. We impose weak economic restrictions to derive...

The new-Keynesian, Taylor-rule theory of inflation determination relies on explosive dynamics. By raising interest rates in response to inflation, the Fed induces ever-larger inflation or deflation, unless inflation jumps to one particular value on each date. However, economics does not rule out...