  The correlation matrix formalism is used to study temporal aspects of the
stock market evolution. This formalism allows to decompose the financial
dynamics into noise as well as into some coherent repeatable intraday
structures. The present study is based on the high-frequency Deutsche
Aktienindex (DAX) data over the time period between November 1997 and September
1999, and makes use of both, the corresponding returns as well as volatility
variations. One principal conclusion is that a bulk of the stock market
dynamics is governed by the uncorrelated noise-like processes. There exists
however a small number of components of coherent short term repeatable
structures in fluctuations that may generate some memory effects seen in the
standard autocorrelation function analysis. Laws that govern fluctuations
associated with those various components are different, which indicates an
extremely complex character of the financial fluctuations.
