relation: http://eprints.imtlucca.it/1877/ title: From Minority Games to real markets creator: Challet, Damien creator: Chessa, Alessandro creator: Marsili, Matteo creator: Zhang, Yi-Cheng subject: QC Physics description: We address the question of market efficiency using the Minority Game (MG) model. First we show that removing unrealistic features of the MG leads to models which reproduce a scaling behaviour close to what is observed in real markets. In particular we find that (i) fat tails and clustered volatility arise at the phase transition point and that (ii) the crossover to random walk behaviour of prices is a finite-size effect. This, on one hand, suggests that markets operate close to criticality, where the market is marginally efficient. On the other it allows one to measure the distance from criticality of real markets, using cross-over times. The artificial market described by the MG is then studied as an ecosystem with different species of traders. This clarifies the nature of the interaction and the particular role played by the various populations. publisher: Taylor & Francis date: 2001 type: Article type: PeerReviewed identifier: Challet, Damien and Chessa, Alessandro and Marsili, Matteo and Zhang, Yi-Cheng From Minority Games to real markets. Quantitative Finance, 1 (1). pp. 168-176. ISSN 1469-7696 (2001) relation: http://www.tandfonline.com/doi/abs/10.1080/713665543 relation: 10.1080/713665543