I’m studying investor entrepreneurs—investors who have an entrepreneurial spirit and found their own investment firms rather than work for someone else. I’m specifically interested in those who’ve had outsize success—meaning they’ve been able to compound their capital at an annual rate that exceeds benchmarks like the S&P 500—for a decade or more.

I’ve noticed that many of these investors are opportunistic—that is, the types of investments they make depend on market conditions. The degree of opportunism varies by investor, but the great ones don’t stick with only one thing.

More importantly, I’ve picked up on a simple framework mentioned by multiple seasoned investors. It’s used to gauge what they should or shouldn’t consider investing in. They look at investments through the lens of supply and demand. If investor demand for an investment is high, its price is often higher and its potential return lower. If demand is low, its price is often lower and its potential return higher. These investors have had outsize success with opportunities for which investor demand was low, resulting in their being materially mispriced.

I like the approach of beginning the investment evaluation process by thinking in terms of supply and demand. It’s simple and can put the investment into perspective quickly.