The equilibrium prices in asset markets, as stated by Keynes (1930): "...will be fixed at the point at which the sales of the bears and the purchases of the bulls are balanced." We propose a descriptive theory of finance explicating Keynes' claim that the prices of assets today equilibrate the...

The equilibrium prices in asset markets, as stated by Keynes (1930): "...will be fixed at the point at which the sales of the bears and the purchases of the bulls are balanced." We propose a descriptive theory of finance explicating Keynes' claim that the prices of assets today equilibrate the...

We propose Keynesian utilities as a new class of non-expected utility functions representing the preferences of investors for optimism, defined as the composition of the investor's preferences for risk and her preferences for ambiguity. The optimism or pessimism of Keynesian utilities is...

The use of equilibrium models in economics springs from the desire for parsimonious models of economic phenomena that take human reasoning into account. This approach has been the cornerstone of modern economic theory. We explain why this is so, extolling the virtues of equilibrium theory; then...

Financial innovations that change how promises are collateralized can affect investment, even in the absence of any change in fundamentals. In C-models, the ability to leverage an asset always generates over-investment compared to Arrow Debreu. The introduction of CDS always leads to...

We show that financial innovations that change the collateral capacity of assets in the economy can affect investment even in the absence of any shift in utilities, productivity, or asset payoffs. First we show that the ability to leverage an asset by selling non-contingent promises can generate...

Our paper provides a complete characterization of leverage and default in binomial economies with financial assets serving as collateral. Our Binomial No-Default Theorem states that any equilibrium is equivalent (in real allocations and prices) to another equilibrium in which there is no...

Our paper provides a complete characterization of leverage and default in binomial economies with financial assets serving as collateral. First, our Binomial No-Default Theorem states that any equilibrium is equivalent (in real allocations and prices) to another equilibrium in which there is no...

Our paper provides a complete characterization of leverage and default in binomial economies with financial assets serving as collateral. Our Binomial No-Default Theorem states that any equilibrium is equivalent (in real allocations and prices) to another equilibrium in which there is no...

Most theories of risky choice postulate that a decision maker maximizes the expectation of a Bernoulli (or utility or similar) function. We tour 60 years of empirical search and conclude that no such functions have yet been found that are useful for out-of-sample prediction. Nor do we find...