Based on the tick-by-tick price changes of the companies from the U.S. and
from the German stock markets over the period 1998-99 we reanalyse several
characteristics established by the Boston Group for the U.S. market in the
period 1994-95, which serves to verify their space and time-translational
invariance. By increasing the time scales we find a significantly more
accelerated crossover from the power-law (alpha approximately 3) asymptotic
behaviour of the distribution of returns towards a Gaussian, both for the U.S.
as well as for the German stock markets. In the latter case the crossover is
even faster. Consistently, the corresponding autocorrelation functions of
returns and of the time averaged volatility also indicate a faster loss of
memory with increasing time. This route towards efficiency may reflect a
systematic increase of the information processing when going from past to
present.Comment: 14 pages, revised versio
