We study a stock market model, consisting in a large number of agents, going eventually to
infinity, and evaluate the stock price under the influence of opinions of different agents. Next
we study the behavior of prices when the market is very nervous; there appear
discontinuities (phase transitions) which can be interpreted as stock market crashes.

In this papcr wc study a stock markct modcl, consisting in a grcat numbcr of agcnts, going
cvcntually to infinity, and wc cvaluatc thc stock pricc undcr thc influcncc of opinions of
diffcrcnt agcnts. Ncxt wc study thc bchaviour of priccs whcn thc markct is vcry ncrvous; thcrc
appcar discontinuitics (phasc transitions) which can bc intcr prctcd as stock markct krachs.