  We investigate the large-fluctuation dynamics in financial markets, based on
the minute-to-minute and daily data of the Chinese Indices and German DAX. The
dynamic relaxation both before and after the large fluctuations is
characterized by a power law, and the exponents $p_\pm$ usually vary with the
strength of the large fluctuations. The large-fluctuation dynamics is
time-reversal symmetric at the time scale in minutes, while asymmetric at the
daily time scale. Careful analysis reveals that the time-reversal asymmetry is
mainly induced by external forces. It is also the external forces which drive
the financial system to a non-stationary state. Different characteristics of
the Chinese and German stock markets are uncovered.
