  We investigate the financial market dynamics by introducing a heterogeneous
agent-based opinion formation model. In this work, we organize the individuals
in a financial market by their trading strategy, namely noise traders and
fundamentalists. The opinion of a local majority compels the market exchanging
behavior of noise traders, whereas the global behavior of the market influences
the fundamentalist agents' decisions. We introduce a noise parameter $q$ to
represent a level of anxiety and perceived uncertainty regarding the market
behavior, enabling the possibility for an adrift financial action. We place the
individuals as nodes in an Erd\"os-R\'enyi random graph, where the links
represent their social interaction. At a given time, they assume one of two
possible opinion states $\pm 1$ regarding buying or selling an asset. The model
exhibits such fundamental qualitative and quantitative real-world market
features as the distribution of logarithmic returns with fat-tails, clustered
volatility, and long-term correlation of returns. We use Student's t
distributions to fit the histograms of logarithmic returns, showing the gradual
shift from a leptokurtic to a mesokurtic regime, depending on the fraction of
fundamentalist agents. We also compare our results with the distribution of
logarithmic returns of several real-world financial indices.

Statistical Finance;Statistical Mechanics