The purpose of this paper is to suggest a new theory of portfolio selection which is based on evolutionary reasoning in simple repeated market situations. According to this new point of view the ultimate success of a portfolio strategy is measured by the wealth share the strategy is eventually able to conquer in an evolutionary process of market selection. We identify a simple portfolio strateg...

This paper investigates the impact of a 'free drug program' on the market equilibrium of drugs. We introduce a screening model of the hard drug market in which dealers use payment and punishment options to screen between high and low risk users. We show that, if a free drug program selects sufficiently many high-risk drug users, the pure-strategy separating market equilibrium ceases to exist an...