  The problem of insider trading and other illegal practices in financial
markets is an important issue in the field of financial regulatory policies.
Market control bodies, such as the US SEC or the Italian CONSOB regularly
perform statistical analyses on security prices in order to unveil clues of
fraudulent behaviour within the market. Fraudulent behaviour is connected to
the more general problem of information asymmetries, which had already been
addressed in the field of experimental economics. Recently, interesting
conclusions were drawn thanks to a computer-simulated market where agents had
different pieces of information about the future dividend cash flow of
exchanged securities. Here, by means of an agent-based artificial market: the
Genoa Artificial Stock Market (GASM), the more specific problem of fraudulent
behaviour in a financial market is studied. A simplified model of fraudulent
behaviour is implemented and the action of fraudulent agents on the statistical
properties of simulated prices and the agent wealth distribution is
investigated.
