Who is Ronald Muhlenkamp?
Ronald Muhlenkamp founded Muhlenkamp & Company in 1977 and launched the Muhlenkamp Fund (MUHLX) in 1988, after building a proprietary method for valuing stocks and bonds in the early 1970s that he still uses. The Muhlenkamp Screen distills his approach into a single rule of thumb: own good companies, but only at a reasonable price. Over the ten-year window AAII measured, his fund averaged 10.4% a year against 8.5% for the S&P 500 — the kind of steady edge his quality-at-a-value-price discipline is built to produce.
The core idea: a good company at a bargain price
Muhlenkamp's gauge of a good company is return on equity — annual earnings divided by shareholders' equity, a direct read on how much profit management wrings from the capital owners have left in the business. He wants that number both high and durable, not a single strong year flattered by a one-off. His bar for "high" comes from history: the average return on equity of American companies since World War II has run near 14%, so he treats above-average profitability as the entry ticket. The second half of the discipline is price. Muhlenkamp will not overpay for quality — his rule is to pay no more than about twice book value, which in a normal-inflation setting works out to roughly 17 times earnings. He ties that ceiling to inflation and interest rates: a stock has to clear what an investor could earn on Treasury bills and corporate bonds, plus a premium for equity risk, so when inflation and rates are low he can pay a higher multiple, and when they are high the multiple he will accept falls.
What the Muhlenkamp Screen looks for
- Return on equity over the trailing 12 months is greater than 9.1%.
- Average return on equity over the last five fiscal years is also greater than 9.1% — evidence the profitability is durable, not a one-year spike.
- The current price-earnings ratio is below 22.
- Five-year compound growth in fully diluted earnings per share from continuing operations is positive.
- That five-year earnings growth rate is at least the median for the company's industry.
- Five-year compound sales growth is at least as high as the five-year earnings growth rate — the bottom line is backed by real revenue.
- Net margin over the trailing 12 months is above the industry median.
- Operating margin over the trailing 12 months is above the industry median.
- Total liabilities as a share of total assets is below the industry median — a check on balance-sheet strength.
- Free cash flow per share over the trailing 12 months is zero or positive.
- The company is based in the United States, not an ADR or ADS.
- The stock trades on the New York, American, or Nasdaq exchanges, not over the counter.
The codified screen sets its profitability floor at a return on equity above 9.1%, both current and five-year average, and caps the price-earnings ratio at 22 — looser numbers than Muhlenkamp's own 14% and 17-times rules of thumb, because the screen is a fixed proxy for a framework he keeps adjusting as inflation and rates move.
Why ROE and a low price belong together
The link between the filters is Muhlenkamp's insight that a high return on equity is what lets a company grow without hurting shareholders. When return on equity exceeds the growth rate, the business funds its own expansion and still throws off free cash — no need to issue shares that dilute owners or pile on debt that has to be serviced through a downturn. That is why he starts from return on equity rather than raw growth. The rest of the screen guards the quality: sales growth at least matching earnings growth keeps the bottom line honest, margins above the industry median point to a real competitive edge, and below-median liabilities-to-assets keeps borrowing from flattering the return figure. Buying all of that at a low multiple is where the return comes from — you collect the quality without paying the quality premium.
What to keep in mind
Return on equity can be manufactured with debt, which is why the balance-sheet and free-cash-flow filters matter — read them alongside the return figure, not around it. The bigger risk is temperament. A value discipline like this sits out the market's hottest phases and can trail badly when glamour leads. Muhlenkamp himself warns of "climate change" — the handful of moments in a generation when the public reprices something fundamental and the old playbook stops working. He answers it by adjusting his benchmarks to inflation and rates, something a screen with fixed cutoffs cannot do. His sell rule is a useful tell: he exits when relative strength breaks down or the fundamentals disappoint. And quality bought cheap is still a value trap if the moat quietly erodes.
Sources
Ron's Road to Wealth: Insights for the Curious Investor, Ronald Muhlenkamp, John Wiley & Sons, 2008.
American Association of Individual Investors (AAII) — Stock Investor Pro screen definition and commentary.