  We address microscopic, agent based, and macroscopic, stochastic, modeling of
the financial markets combining it with the exogenous noise. The interplay
between the endogenous dynamics of agents and the exogenous noise is the
primary mechanism responsible for the observed long-range dependence and
statistical properties of high volatility return intervals. By exogenous noise
we mean information flow or/and order flow fluctuations. Numerical results
based on the proposed model reveal that the exogenous fluctuations have to be
considered as indispensable part of comprehensive modeling of the financial
markets.
