The Philosophy Lurking in Your Portfolio

© Can Stock Photo Inc. / Paul_Cowan

Modernism is a philosophical movement that arose from the far-reaching transformations Western society underwent in the late 19th century. This gave way to the skepticism of the late 20th century which led to the movement we call Post-Modernism.

This sets the stage for our discussion of Modern Portfolio Theory (MPT), and our response to it.

If you have ever seen the customary asset allocation pie chart or heard talk of getting exposure to all the major ‘asset classes’ then you have been exposed to MPT. It presumes that historical data about the behavior of all the various kinds of investments enables computers to calculate the best mix of holdings to get the returns we desire with the lowest level of risk. One investment zigs when another one zags, leaving the total portfolio steadier than it otherwise would be.

Great theory. Here are the problems that arise in practice:

1. At times of greatest stress in the markets, when you most need MPT to work, the historical correlations go away and the most overpriced assets get slammed regardless of what the computer thought.
2. Common sense and fundamental investment analysis often reveal that one slice of the asset pie is likely to leave a very bitter taste. Large growth stocks in 2000, real estate in 2007, commodities in 2011…everybody knows now that the best allocation to these overpriced bubbles was ZERO.
3. Although the discipline of MPT reduces the damage from counterproductive crowd behavior, it neither eliminates the damage nor allows one to profit from the madness of crowds.

Our investment management approach, forged in the skepticism born of deep knowledge of MPT, is based on three fundamental principles. We believe these principles are timeless, suitable for any market. We have written about them before, we will write about them again, and we have talked incessantly about them for twenty years. For now let us simply note that, as a reaction to Modern Portfolio Theory, they might collectively best be known as “Postmodern Portfolio Theory.”


The opinions voiced in this material are for general information only and are not intended to provide specific advice or recommendations for any individual.

There is no guarantee that a diversified portfolio will enhance overall returns or outperform a non-diversified portfolio. Diversification does not protect against market risk.