  To investigate the universal structure of interactions in financial dynamics,
we analyze the cross-correlation matrix C of price returns of the Chinese stock
market, in comparison with those of the American and Indian stock markets. As
an important emerging market, the Chinese market exhibits much stronger
correlations than the developed markets. In the Chinese market, the
interactions between the stocks in a same business sector are weak, while extra
interactions in unusual sectors are detected. Using a variation of the
two-factor model, we simulate the interactions in financial markets.
