MSCI to the U.S. market

MSCI to the U.S. market was 0.438 from December 1992
through July 1998. Since then the average has jumped 66 percent
to 0.725, almost the exact same increase in correlations, in percentage
terms, seen in developed stock markets. Since May of
2005, 14 emerging stock markets, including the largest, South
Korea, have registered their highest correlation levels ever compared
to the United States.
In the case of both developed and emerging markets, some of
the change is explained by big moves in dominant countries in
each category.