A key
tenant of modern portfolio theory is that the ownership of a portfolio assets, even risky assets, with low correlations
between them can reduce portfolio risk. The basic idea is that you want Asset B to go up when Asset A goes down and vice
versa so your overall return profile is smooth. One of the key asset classes US investors use to diversify portfolios is International Equities.
By some measures the correlation between US markets and Non-US Equity markets are declining:
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During the two-year period that ended in February, correlation between U.S. and other developed markets was 0.63, according to ING Asset Management. That is a big decline from 2003 to 2005, when they practically moved in lockstep, at 0.93. (The figures are based on monthly movements in the Standard &
Poor's 500-stock index and the Morgan Stanley Capital International
EAFE indexes.)
So far this year U.S. markets have held up well. But foreign markets are doing even better. The Dow Jones World Index, excluding the U.S., is up 8.5% this year in dollar terms, compared with 3.9% for the S&P 500."
However, there is also anecdotal evidence that the economies of the US and other nations may be even more linked than official measures indicate:
"That's because home construction is the principal gateway industry for immigrants entering the U.S. labor market. Those immigrants contribute the lion's share of the estimated $50 billion in cash sent annually from the U.S. to family members and others in countries south of the border. That tide of cash appears to be ebbing.
"Monthly remittances from the U.S. to Mexico have dropped every month since their peak of $2.6 billion in May 2006 -- shortly before new-home construction in the U.S. plunged. In February 2007, the latest month for which data are available, remittances to Mexico had slowed to $1.7 billion.
"Mexico, Latin America's remittance leader, may be a leading indicator of a trend unfolding across the continent. In a recent study of 15 Latin American economies tracked by BCP Securities of Greenwich, Conn., all but three showed better than a 90% correlation between the ebb and flow of U.S. housing starts and the swelling and shrinkage of remittances as recorded by the nations' central banks.
"The contraction in remittances will dampen domestic consumption and hamper [economic] growth rates" in countries ranging from Mexico to Colombia to those in Central America, said the study's author, BCP Securities economist Walter Molano."