The Death of Diversification Has Been Greatly Exaggerated

Abstract

Diversification is famously referred to as the only “free lunch” in investing, but it has been under assault since the 2007–2009 global financial crisis, when virtually all long only asset classes moved down together. Ilmanen and Kizer argue that the attacks are undeserved. Most investors were never as diversified as they thought they were, and there is ample room for improvement by shifting the focus from asset class diversification to factor diversification. They show that diversification into and across factors has been much more effective in reducing portfolio volatility and market directionality than asset class diversification. The benefits are greatest for long–short investing, which requires shorting and leverage but are also meaningful in a long-only context.

Keywords: Diversification, Style Investing, Factor Investing

JEL Classification: G01, G11