Broker Check

Using Modern Portfolio Theory

This is a little longer than the summaries in the Investment Process but I think it is worth it. I'm going to share one of the "secret handshakes" in the retail brokerage world. You might have a few "a ha's" or groans as you compare your experience.

Modern Portfolio Theory (MPT) is the orthodoxy of retail investment advice. It informs the vast majority of strategies and products available to consumers. For our purposes, MPT is a discipline that compares the risk and return patterns of different asset classes (stocks, bonds, commodities, etc.) over long periods of time. Those individual patterns tend to stay in a range of gains, losses and price fluctuations during a market cycle. The time it takes to complete a cycle also differs. Asset patterns correlate differently with each other. Some rise and fall similarly while others do almost the opposite. In theory (and it is only a theory), diversifying among different asset classes potentially reduces overall portfolio volatility for a given return than owning a single asset.

You can find out a lot more about this by researching "the Efficient Frontier".


I use MPT extensively as a valuable financial planning tool.

I do not use it to create portfolios.

Here's why:
After the 1987 crash (and I had a ringside seat), investment firms looked for ways to reduce the volatility in their clients' accounts and still stay on track for returns. They adapted institutional risk management techniques to fit smaller account sizes and started recommending more prudent strategies industry-wide.

An added benefit was that they made research much more efficient. When I got into the business, everybody did their own homework. Whether they did it well or not, it took time. As firms packaged MPT into asset allocation models, brokers could concentrate on serving clients and finding new ones.

"Experts" made the strategic decisions. All you needed to do was match an investor's assets, time horizon and risk tolerance to a pre-set allocation. The icing on the cake was that some of these allocation packages were more lucrative than ordinary stock and bond trading

More ominously, MPT-based platforms were assumed to minimize risk. Every day was a good day to buy. Short-term timing flaws would be corrected by rising long-term patterns. After all, they were managed by "Experts"!

Some brokers lost the habit of doing their own research. Insurance agents, banks and tax advisors could sell the new packaged products without a traditional securities registration. In short, a lot of advisors were completely dependent on their parent company or product vendors for strategic guidance.

Then came the bear market. The tech crash of 2000 was a shot across the bow. The financial meltdown of 2008 was the hammer. MPT correlations collapsed. The asset correlations that support MPT collapsed. With no exit strategy, advisors looked helplessly to their companies - many of whom were already insolvent from undisclosed derivative trading schemes and not inclined to share lifeboats with brokers, shareholders or clients.

Stock market average are well into the black again1 - better than a lot of firms who sold them. That is cold comfort to clients who bailed-out and are still waiting in their foxholes. The discipline to hold any strategy was sorely tested in the free-fall of 2008. A lot of those advisors are bussing tables now.

Some firms are still using the same pie-chart buy-and-hold models as if nothing happened. Allocations hardly changed.

This is where I usually hear, "You can't time the markets." That is a fair challenge and deserves a reasoned response. I like owning stocks and try to stay invested as much as I can. That means riding through choppy markets and some gut-churning drops. It comes with the territory. But trends tend to continue until acted on by a greater force. When an investment is heading south, there are telltale indicators whether it is within a familiar range or has violated import levels of buyer support. These indicators often conflict and aren't obvious until some damage has already been done. I carefully study those signals to try and tell the difference between a routine correction and something worse.

Thanks for staying with me so long. Now let me tell you what I do.

My methodology is constantly looking for positive relative price strength among asset groups. Any investment we consider for your portfolio has to undergo rigorous testing against almost every other kind of investment before it makes the cut. And it has to make the cut every day thereafter. Think of it as a sports team. We don't keep veterans with creaky knees for sentimental reasons. I certainly won't purchase weak investments because they round out the portfolio.

At the same time, I maintain a rigid risk discipline. As we learned above, every day is not a good day to buy. The price you pay for an investment matters. My risk screens tell me how enthusiastic I should be about even promising investments. We don't want the best house in a bad neighborhood. I will hold cash and I will completely eliminate certain asset classes if they cross the wrong lines.

There is an exit strategy with every investment. You will know, in advance, what we hope to do if we're right, the options if a position doesn't work and how I monitor your situation. We will meet or talk at least quarterly and you are always welcome to call in between.

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1 SPX October 2007 1557 points, June 2014 1960 points