Numbers can lie -- but they're the best first step in determining whether a stock is a buy. In this series, we use some carefully chosen metrics to size up a stock's true value based on the following clues:

  • The current price multiples.
  • The consistency of past earnings and cash flow.
  • How much growth we can expect.

Let's see what those numbers can tell us about how expensive or cheap AK Steel Holding (NYSE: AKS) might be.

The current price multiples
First, we'll look at most investors' favorite metric: the P/E ratio. It divides the company's share price by its earnings per share -- the lower, the better.

Then, we'll take things up a notch with a more advanced metric: enterprise value to unlevered free cash flow. This divides the company's enterprise value (basically, its market cap plus its debt, minus its cash) by its unlevered free cash flow (its free cash flow, adding back the interest payments on its debt). Like the P/E, the lower this number is, the better.

Analysts argue about which is more important -- earnings or cash flow. Who cares? A good buy ideally has low multiples on both.

AK Steel has negative P/E and EV/FCF ratios over the trailing 12 months. If we stretch and compare current valuations to the five-year averages for earnings and free cash flow, AK Steel has a P/E ratio of 27.0 and a negative five-year EV/FCF ratio.

A positive one-year ratio under 10 for both metrics is ideal (at least in my opinion). For a five-year metric, under 20 is ideal.

AK Steel is zero for four on hitting the ideal targets, but let's see how it compares against some competitors and industry mates. 

Company

1-Year P/E

1-Year EV/FCF

5-Year P/E

5-Year EV/FCF

AK Steel NM NM 27.0 NM
Allegheny Technologies (NYSE: ATI) 25.7 NM 14.4 135.0
Carpenter Technology (NYSE: CRS) 29.3 NM 21.4 42.4
Steel Dynamics (Nasdaq: STLD) 11.1 13.3 10.6 18.4

Source: S&P Capital IQ; NM = not meaningful  because of losses.

Numerically, we've seen how AK Steel's valuation rates on both an absolute and relative basis. Next, let's examine...

The consistency of past earnings and cash flow
An ideal company will be consistently strong in its earnings and cash flow generation.

In the past five years, AK's net income margin has ranged from -12.9% to 6.9%. In that same time frame, unlevered free cash flow margin has ranged from -10.2% to 6.3%.

How do those figures compare with those of the company's peers? See for yourself:

Source: S&P Capital IQ; margin ranges are combined.

Additionally, over the last five years, AK Steel has tallied up three years of positive earnings and two years of positive free cash flow.

Next, let's figure out...

How much growth we can expect
Analysts tend to comically overstate their five-year growth estimates. If you accept them at face value, you will overpay for stocks. But while you should definitely take the analysts' prognostications with a grain of salt, they can still provide a useful starting point when compared to similar numbers from a company's closest rivals.

Let's start by seeing what this company's done over the past five years. Because of losses, AK's trailing growth rate isn't meaningful. Meanwhile, its peers have severe negative growth:

Source: S&P Capital IQ; EPS growth shown.

And here's how it measures up with regard to the growth analysts expect over the next five years:

Source: S&P Capital IQ; estimates for EPS growth.

The bottom line
The pile of numbers we've plowed through has shown us the price multiples shares of AK Steel are trading at, the volatility of its operational performance, and what kind of growth profile it has -- both on an absolute and a relative basis.

The more consistent a company's performance has been and the more growth we can expect, the more we should be willing to pay. We've gone well beyond looking at a negative P/E ratio, and we see that some of AK's difficulties are because of the recent dynamics of the steel industry. However, its peers all have better historical margins, and AK is the only one with negative one-year earnings. The initial numbers ain't pretty. Check out its most recent earnings as confirmation.

I probably won't be going much further with AK Steel, but if you find AK Steel's initial numbers or story compelling, don't stop. Continue your due diligence process until you're confident one way or the other. As a start, add it to My Watchlist to find all of our Foolish analysis.

To see the stocks that I've researched beyond the initial numbers and bought in my public real-money portfolio, click here.