Evolutionary Stability of Portfolio Rules in Incomplete Markets

This paper studies the evolution of market shares of portfolio rules in incomplete markets with short-lived assets. Prices are determined endogenously. The performance of a portfolio rule in the process of continuous reinvestment of wealth is determined by the market share eventually conquered in competition with other portfolio rules. Using random dynamical systems theory, we derive necessary and sufficient conditions for the evolutionary stability of portfolio rules. In the case of Markov (in particular i.i.d.) payoffs these local stability conditions lead to a simple portfolio rule that is the unique evolutionary stable strategy. This rule possesses an explicit representation. Moreover, it is demonstrated that mean-variance optimization is not evolutionary stable while the CAPM-rule always imitates the best portfolio rule and survives.evolutionary finance; portfolio theory; market selection; incomplete markets

Risk Aversion in the Large and in the Small

Estimates of agents' risk aversion differ between market studies and experimental studies. We demonstrate that the estimates can be reconciled through consistent treatment of agents' tendency for narrow framing, regarding integration of background wealth as well as across risky outcomes: Risk aversion is similar whenever similar degrees of narrow framing is assumed in either setting.Risk aversion; narrow framing; background wealth; laboratory experiments; market studies; equity premium puzzle

Survival of the Fittest on Wall Street

This paper studies an application of a Darwinian theory of portfolio selection to stocks listed in the Dow Jones Industrial Average (DJIA). We analyze numerically the long-run outcome of the competition of fix-mix portfolio rules in a stock market with actual DJIA dividends. In the model seemingly rational strategies can do very poorly against seemingly irrational strategies. Moreover, the interaction of strategies can lead to stochastic time series of asset prices that do not converge. The simulations also show that the evolutionary portfolio rule discovered in Hens and Schenk-Hopp´e (2004) will eventually hold total market wealth in competition with fix-mix portfolio rules derived from mean-variance optimization, maximum growth theory and behavioral finance. According to this evolutionary rule, portfolio weights should be proportional to the expected relative dividends of the assets. As an implication asset prices converge to expected relative dividends.Evolutionary Finance; Behavioral Finance; CAPM; Fix-Mix Portfolio Rules; Growth Optimal Portfolio

Markets Do Not Select For a Liquidity Preference as Behavior Towards Risk

Tobin (1958) has argued that in the face of potential capital losses on bonds it is reasonable to hold cash as a means to transfer wealth over time. It is shown that this assertion cannot be sustained taking into account the evolution of wealth of cash holders versus non cash holders. Cash holders will be driven out of the market in the long run by traders who only use a (risky) long-lived asset to transfer wealth.demand for money; portfolio theory; evolutionary finance

Prospect Theory around the World

We present results from the first large-scale international survey on risk preferences, conducted in 45 countries. We show substantial cross-country differences in risk aversion, loss aversion and probability weighting. Moreover, risk attitudes in our sample depend not only on economic conditions, but also on cultural factors, as measured by the Hofstede dimensions Individuality and Uncertainty Avoidance. The presented data might also serve as an interesting starting point for further research in cultural economics.Risk preferences; prospect theory; cross-cultural comparison

Strategic asset allocation and market timing: a reinforcement learning approach

We apply the recurrent reinforcement learning method of Moody, Wu, Liao, and Saffell (1998) in the context of the strategic assetallocation computed for sample data from US, UK, Germany, and Japan. It is found that the optimal assetallocation deviates substantially from the fixed-mix rule. The investor actively times the market and he is able to outperform it consistently over the almost two decades we analyz

How Time Preferences Differ: Evidence from 45 Countries

We present results from the first large-scale international survey on time discounting, conducted in 45 countries. Cross-country variation cannot simply be explained by economic variables such as interest rates or in ation. In particular, we find strong evidence for cultural differences, as measured by the Hofstede cultural dimensions. For example, high levels of Uncertainty Avoidance or Individualism are both associated with strong hyperbolic discounting. Moreover, as application of our data, we find evidence for an impact of time preferences on the capability of technological innovations in a country and on environmental protection.Time preferences; Intertemporal decision; Endogenous preference; Cross-cultural comparison