INVESTING: Modern portfolio theory may spawn mediocre returns
A tenet of modern portfolio theory is the call to diversify. Over the long haul, equities have gone up twothirds of the time. That means losses have occurred onethird of the time-and they’ve sometimes been severe. Hypothetically, a greater mix of asset classes should protect against the downside and perhaps even provide a portfolio with gains even when equities are down. But diversify into what? Thirty years ago, when modern portfolio theory was just gaining ground, investors had few choices….
