If there’s any consensus in the business of managing money, diversification probably comes closest to the ideal of strategic agreement and accord. Diversification, after all, is your only friend in the long run. Timing the market and choosing securities is far more exciting, but who among us thinks such high arts can be sustained?
The alternative, of course, is the time-tested antidote of diversification, which is the only effective defense against the great unknown, otherwise known as tomorrow. Since no one really knows what’s coming, prudence dictates the embrace of diversification, at least for us mere mortals who have no chance at becoming the next George Soros or Warren Buffett.
To be sure, not all diversification is enlightened. Owning three tech-stock funds, for example, doesn’t come close to informed diversification.
Yes, it’s true that there’s no shortage of debate about what constitutes a prudent level of diversification. But there are some ground rules, starting with the fact that investors should have exposure to the various asset classes. We’re defining asset classes as those groups that exhibit relatively unique characteristics that distinguish them from other groups. Price correlation is one way to measure such characteristics.
Bonds and stocks, to cite the obvious example, post a sufficiently low correlation with each other over time so as to warrant embracing them as separate and distinct asset classes. What that means is that there’s a good chance that when one’s losing money, the other will be holding its own, if not posting gains. In fact, history shows just that. Owning bonds in 2000-2002, for instance, offered valuable ballast when the stock market was suffering.
But how do you protect a portfolio when bonds are under attack? Traditionally, stocks can help, although the record shows that stocks and bonds have been known to tank together at times–this limited form of diversification fades just when you need it most. Meanwhile, cash is an asset class in its own right, and always holds its value, at least in nominal terms, which makes it an essential candidate for diversification. But holding too much cash opens one to the inflation threat over time.
The true solution is embracing a broader array of asset classes. That’s not been easy for individual investors in the past, but as mutual funds and exchange traded funds bring formerly exotic asset classes to the masses, quite often in cost-efficient index-fund packages, the opportunity for greater diversification is here.
The question then becomes: is more diversification better? In search of an answer, or at least some perspective, we crunched the numbers on 10 asset classes (courtesy of Morningstar and Dow Jones) for the decade through the end of 2005 and compared three diversification strategies:
1) an equal mix of U.S. stocks, U.S. bonds and cash
2) an equal mix of 10 asset classes
3) a traditional pension-fund-inspired 60% U.S. stocks/40% U.S. bonds mix
The asset classes for the three strategies are based on returns from the following indices, most of which are available via index funds or an actively managed fund that serves as a proxy:
1. U.S. Stocks (Russell 3000)
2. U.S. bonds–Treasuries, corporates, mortgaged backed (Lehman Brothers Aggregate)
3. Cash (3 Month T-bill)
4. Emerging markets debt (Citigroup ESBI-Cap Brady, in dollars)
5. Foreign government bonds, developed countries (Citigroup Non-$ World Govt, in dollars)
6. U.S. high yield debt (CSFB High Yield)
7. Foreign developed markets stocks (MSCI EAFE, in dollars)
8. Foreign emerging markets stocks (MSCI EM, in dollars)
9. Real estate investment trusts (Wilshire REIT)
10. Commodities (DJ-AIG Index)