  We study the inter-stock correlations for the largest companies listed on
Warsaw Stock Exchange and included in the WIG20 index. Our results from the
correlation matrix analysis indicate that the Polish stock market can be well
described by a one factor model. We also show that the stock-stock correlations
tend to increase with the time scale of returns and they approach a saturation
level for the time scales of at least 200 min, i.e. an order of magnitude
longer than in the case of some developed markets. We also show that the
strength of correlations among the stocks crucially depends on their
capitalization. These results combined with our earlier findings together
suggest that now the Polish stock market situates itself somewhere between an
emerging market phase and a mature market phase.
