In other words, global diversification helps to improve the risk-adjusted performance of the portfolio.

FORBES: Why Global Diversification Still Makes Sense

All investors, professional or novice, who are looking for global diversification, will benefit from a careful read of the insights provided in this book.

FORBES: Communism Is Dead, But State Capitalism Thrives

It takes a keen interest in Vale's activities and has never been keen on global diversification, preferring that the company build its business at home.

ECONOMIST: An acquisition in aluminium

Unlike the Mortgage REIT and MLP sectors which investors have also flocked to, the sector does not offer defensive traits if the economy stumbles, and they have little to no global diversification.

FORBES: The ABCs of BDCs: High Yields Have Their Price

Just two index funds like the Vanguard Total Stock Market and Total International Stock Index provide effective, economical, tax efficient global equity diversification.

FORBES: Dealing With A Crummy 401(k) Plan

Now in a new book Malkiel moves on to extol the virtues of global portfolio diversification--in index funds and actively managed funds -- at a time when many investors are licking their wounds from Southeast Asia, Russia and, not so long ago, Latin America.

FORBES: About Burton Malkiel

Moreover, the independent movement of global markets, which react to factors such as different domestic monetary and fiscal policy cycles, has historically provided considerable diversification benefits when held in combination with US investments (though correlations tend to converge on 1 in periods of financial crisis).

FORBES: Why Global Diversification Still Makes Sense

Given the many moving pieces in the complex, global investment puzzle, investors would be wise to revisit their asset allocation strategies to help ensure that they have the diversification in place to withstand potential periods of heightened volatility as well as the breadth of asset classes and sectors to help deliver risk adjusted growth opportunities.

FORBES: 5 Top Investment Themes For 2013