Portfolio Benchmarking: 5-Reasons Underperformance Occurs

When markets decline—especially after long periods of sustained growth—the familiar advice resurfaces: “Be patient. Stay invested. Ride it out.” The rationale? The market always goes up over time. But there’s a critical flaw in this narrative.

Your portfolio and a portfolio benchmark are entirely different things.

And portfolio benchmarking, or the constant comparison of your performance to major indices like the S&P 500, can be dangerously misleading for real-world investors. Here’s why.

1) Markets Do Not Compound Returns

One of the most critical fallacies of portfolio benchmarking is the disparity between compound and variable rates of return. To wit:

While the average rate of return may have been 10% over the long term, the markets do not deliver 10% every year. Let’s assume an investor wants to compound their returns by 10% annually over 5 years. We can do some basic math.

annual average return