Based on valuation, this stock is “cheap.”

We are sure you have heard that more than once from a portfolio manager, analyst or other type of market player.

But what if their assumptions for economic growth and earnings are incorrect from the start?

Then that valuation considered “cheap” is immaterial and the stock becomes a trap.

There is a distinct possibility many stocks that appear to have reasonable price-to-earnings valuations right now are a risky bet because of overly optimistic profit margin estimates and rising labour costs.

That’s according to this former hedge fund manager and founder of an investment research company.

**

After the painful decline in stock prices last year, many investors have clearly come to the conclusion that this now represents another terrific buying opportunity.

And if you look just at earnings-based valuation measures, you could be forgiven for thinking that, while they may not be inordinately cheap, equity valuations are no longer extreme.

The forward price-to-earnings ratio now shows the S&P 500 trades at a multiple of around 17, very near its average over the past two decades.

What this measure obscures, however, is the fact that the profit margins supporting those earnings are still obscene.

Moreover, estimates assume the recent decline in margins will soon reverse and that they will return nearly to record highs.

Certainly, there are at least a few reasons (like the strength in the dollar, interest rates and oil prices over the past couple of years) to be skeptical of this optimistic analysis.

Rapidly rising labor costs typically lead to margin declines greater than that we have already seen and labor costs have already risen faster than at any point in the past thirty years.

If profit margins continue to fall over the course of this year, rather than reverse higher as expected, the denominator in those forward price-to-earnings ratios could decline dramatically, revealing the fact that equity valuations were never really all that reasonable in the first place.

They only appear that way today as the result of some especially heroic assumptions on the part of equity analysts.

**

Related stories: Congrats Jay Powell on the Biggest Bubble in History

Learning How to Lose Is Key to Winning in the Market