When you study a company as a possible investment for your portfolio, you probably examine factors such as its debt and cash levels, the growth rates of its revenue and earnings, its profit margins, its return on equity, and its price-to-earnings (P/E) ratio. Those are all good to look at. Another worthwhile measure to check out is this: profit per employee -- or, alternatively, revenue per employee. Here's a look at why you might want to assess a company's profit or revenue per employee, along with a list of companies with high and low scores in that metric. Image source: Getty Images. Revenue per employee Looking at how much revenue a company generates per worker can tell you a lot. It's a measure of efficiency, for starters, as a high number means the company is able to bring in a lot of sales with relatively few workers. Comparing a company's revenue per employee with that of its peers can also let you see which company seems to be more efficient. After all, if you need a lot more workers to achieve the same revenue result as a rival, that means you're paying a lot more in salary and benefits, not to mention overhead related to those workers, such as space in offices and/or other worksites. It's not always worth comparing a company's number to other companies in different industries, as some industries simply require more or fewer workers. It's also informative to check how a company's revenue per worker has changed over time. If the number is growing, the company is getting more efficient and workers more productive. If it's shrinking, you might want to look into why that might be happening. Revenue numbers for companies can be found in financial statements issued quarterly by publicly traded companies -- on the income statement. (Note that some use the word revenue while others say sales -- they refer to the same thing.) It can be a bit trickier to find the number of employees. The number might be included in quarterly earnings reports or even on the website or in the company's boilerplate section at the end of a press release. You can usually find it in the company's annual 10-K report, too. Searching for the word "employees" or "associates" is usually productive. Who brings in the most and least per worker? So which businesses bring in the most money per worker? Here are lists of the top and bottom 10 companies in the U.S., presented by the folks at smallbusinessprices.co.uk in 2020. (Their methodology: "Using a seedlist from Fortune 500 and Share.com, we were able to look at the top performing companies' revenue figures and compared this to their number of employees.") Here are the companies with the highest revenue per employee: Company Annual Revenue Employees Revenue per Employee A-Mark Precious Metals $7.6 billion 184 $41.3 million StoneX Group $27.6 billion 1,701 $16.2 million Federal National Mortgage Association (Fannie Mae) $120 billion 7,400 $16.2 million Federal Home Loan Mortgage Corp (Freddie Mac) $73.6 billion 6,621 $11.1 million Valero Energy $111.4 billion 10,261 $10.9 million PBF Energy $27.2 billion 3,266 $8.3 million AmerisourceBergen $167.9 billion 20,500 $8.2 million Phillips 66 $114.2 billion 14,200 $8.0 million World Fuel Services $39.8 billion 5,000 $8.0 million NGL Energy Partners $17.3 billion 2,400 $7.2 million Data source: Smallbusinessprices.co.uk, using data from the Fortune 500 and Share.com. And here are the U.S. companies with the lowest revenue per employee: Company Annual Revenue Employees Revenue per Employee Yum China Holdings $8.4 billion 450,000 $18,700 Darden Restaurants $8.1 billion 180,656 $44,726 ABM Industries $6.4 billion 140,000 $46,016 Hilton Worldwide Holdings $8.9 billion 169,000 $52,698 Cognizant Technology Solutions $16.1 billion 281,600 $57,262 Aramark $15.8 billion 227,200 $69,497 Starbucks $XX billion 291,000 $84,947 Synnex $XX billion 231,600 $86,588 Hanesbrands $XX billion 68,000 $100,059 McDonald's $XX billion 210,000 $100,120 Data source: Smallbusinessprices.co.uk, using data from the Fortune 500 and Share.com. Image source: Getty Images. Profits per employee It can also be informative to check out profits per employee, and some investors prefer such numbers, because while a company might generate massive revenue, that doesn't necessarily translate to massive profits. Below are profits per worker for a bunch of high-profile tech companies. Company Annual Profit Employees Profit per Employee Facebook $18.5 billion 44,942 $411,308 Apple $55.3 billion 137,000 $403,328 Alphabet $34.3 billion 118,899 $288,842 Microsoft $39.2 billion 144,000 $272,500 Lam Research $2.2 billion 10,700 $204,804 NVIDIA $2.8 billion 13,775 $202,976 Intel $21.0 billion 110,800 $189,964 Booking Holdings $4.9 billion 26,400 $184,280 Micron Technology $6.3 billion 37,000 $170,622 Texas Instruments $5.0 billion 29,768 $168,537 Data source: Fortune.com, using data by Tipalti. As you study companies to see which ones might deserve berths in your portfolio, take a look at revenue -- and/or profit -- per employee to see how efficient and productive they are. 10 stocks we like better than WalmartWhen investing geniuses David and Tom Gardner have an investing tip, it can pay to listen. 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The Motley Fool owns shares of and recommends Alphabet (A shares), Alphabet (C shares), Apple, Booking Holdings, Cognizant Technology Solutions, Facebook, Lam Research, Microsoft, NVIDIA, and Starbucks. The Motley Fool owns shares of Texas Instruments. The Motley Fool recommends Intel and recommends the following options: long January 2021 $85 calls on Microsoft, short January 2021 $115 calls on Microsoft, and short November 2020 $85 calls on Starbucks. The Motley Fool has a disclosure policy.Source