Aecom (NYSE: ACM) trades at a P/E multiple of 14.3x, which is lower than the Industrials sector median of 24.5x. While this makes ACM appear like a stock to add to your portfolio, you might change your mind after gaining a better understanding of the assumptions behind the P/E ratio. In this article, I will break down what the P/E ratio is, how to interpret it and what to watch out for.

##### Understanding Valuation Multiples and the P/E Ratio

A Multiples Valuation, also known as a Comparable Companies Analysis, determines the value of a subject company by benchmarking the subject’s financial performance against similar public companies (Peer Group). We can infer if a company is undervalued or overvalued relative to its peers by comparing metrics like growth, profit margin, and valuation multiples.

A P/E Multiple is a valuation ratio that indicates the multiple of earnings investors are willing to pay for one share of a company:

`P/E Multiple = Stock Price ÷ Earnings Per Share`

The P/E ratio is not meant to be viewed in isolation and is only useful when comparing it to other similar companies. Since it is expected that similar companies have similar P/E ratios, we can come to some conclusions about the stock if the ratios are different. I compare Aecom’s P/E multiple to those of Fluor Corporation (NYSE: FLR), Jacobs Engineering Group Inc. (NYSE: JEC), MasTec, Inc. (NYSE: MTZ) and Dycom Industries, Inc. (NYSE: DY) in the chart below.

Since Aecom’s P/E of 14.3x is lower than the median of its peers (33.5x), it means that investors are paying less than they should for each dollar of ACM’s earnings. As such, our analysis shows that ACM represents an undervalued stock. In fact, finbox.io’s P/E Multiple Model calculates a fair value of \$61.10 per share which implies a significant 68.3% upside.

Note that the selected multiple of 24.1x in the analysis above was determined by averaging Aecom’s current P/E multiple with its peer group and sector.

##### Understanding the P/E Ratio’s Limitations

Before jumping to the conclusion that Aecom should be added to your portfolio, it is important to understand that our conclusion rests on two important assumptions.

(1) the selected peer group actually contains companies that truly are similar to Aecom, and

(2) the selected peer group stocks are being fairly valued by the market.

If the first assumption is not accurate, the difference in P/E ratios could be due to a variety of factors. For example, if you accidentally compare Aecom with higher growth companies, then its P/E multiple would naturally be lower than its peers since investors reward high growth stocks with a higher price.

source: P/E model

Now if the second assumption does not hold true, Aecom’s lower multiple may be because firms in our peer group are being overvalued by the market.

##### What This Means For Investors

As a shareholder, you may have already conducted fundamental analysis on the stock so its current undervaluation could signal a potential buying opportunity to increase your position in ACM. However, keep in mind the limitations of the P/E ratio when making investment decisions. There are a variety of other fundamental factors that I have not taken into consideration in this article. If you have not done so already, I highly recommend you to complete your research on Aecom by taking a look at the following:

Valuation Metrics: what is Aecom’s free cash flow yield and how does it compare to its publicly traded peers? This metric measures the amount of free cash flow for each dollar of equity (market capitalization). Analyze the free cash flow yield here.

Risk Metrics: what is Aecom’s CapEx coverage? This is the amount a company outlays for capital assets for each dollar it generates from those investments. View the company’s CapEx coverage here.

Forecast Metrics: what is Aecom’s projected EBITDA margin? Is the company expected to improve its profitability going forward? Analyze the company’s projected EBITDA margin here.

##### Author: Matt Hogan

Expertise: Valuation, financial statement analysis

Matt Hogan is also a co-founder of finbox.io. His expertise is in investment decision making. Prior to finbox.io, Matt worked for an investment banking group providing fairness opinions in connection to stock acquisitions. He spent much of his time building valuation models to help clients determine an asset’s fair value. He believes that these same valuation models should be used by all investors before buying or selling a stock.

His work is frequently published at InvestorPlace, Benzinga, ValueWalk, AAII, Barron’s, Seeking Alpha and investing.com.

Matt can be reached at matt@finbox.io.

As of this writing, I did not hold a position in any of the aforementioned securities and this is not a buy or sell recommendation on any security mentioned.

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