  World currency network constitutes one of the most complex structures that is
associated with the contemporary civilization. On a way towards quantifying its
characteristics we study the cross correlations in changes of the daily foreign
exchange rates within the basket of 60 currencies in the period December 1998
-- May 2005. Such a dynamics turns out to predominantly involve one outstanding
eigenvalue of the correlation matrix. The magnitude of this eigenvalue depends
however crucially on which currency is used as a base currency for the
remaining ones. Most prominent it looks from the perspective of a peripheral
currency. This largest eigenvalue is seen to systematically decrease and thus
the structure of correlations becomes more heterogeneous, when more significant
currencies are used as reference. An extreme case in this later respect is the
USD in the period considered. Besides providing further insight into subtle
nature of complexity, these observations point to a formal procedure that in
general can be used for practical purposes of measuring the relative currencies
significance on various time horizons.

Statistical Finance;Physics and Society