Relations, Risks, Portfolio Theory and Key Natural Laws in Economics

Relations Between Theory and Model in Psychology and Economics

Modern Portfolio Theory, Digital Portfolio Theory and Intertemporal Portfolio Choice

The paper compares three portfolio optimization models. Modern portfolio theory (MPT) is a short-horizon volatility model. The relevant time horizon is the sampling interval. MPT is myopic and implies that investors are not concerned with long-term variance or mean-reversion. Intertemporal portfolio choice is a multiple period model that revises portfolios continuously in response to relevant s...

Power Laws in Economics and Finance

A power law (PL) is the form taken by a large number of surprising empirical regularities in economics and finance. This review surveys well-documented empirical PLs regarding income and wealth, the size of cities and firms, stock market returns, trading volume, international trade, and executive pay. It reviews detailindependent theoretical motivations that make sharp predictions concerning th...

Power laws in economics and elsewhere

We review power laws in financial economics. This is a chapter from a preliminary draft of a book called “Beyond equilibrium and efficiency”. While some of the discussion is specific to economics, most of it applies to power laws in general – the nouns may change, but the underlying questions are similar in many fields. This draft is still preliminary and not entirely finished – comments at any...

Of Economics Costly Portfolio Adjustment

This paper studies the dynamic optimization problem of a household when portfolio adjustment is costly. The analysis is motivated by the observation that on a monthly basis, less than 10% of stockholders typically adjust their portfolio of common stocks. We use this, and related observations, to estimate the parameters of household preferences and portfolio adjustment costs. We find significant...