The world’s largest companies have many similarities, but the size of their respective org charts is not necessarily one of them.

At the one extreme, companies such as Walmart require a massive workforce in the millions to run retail operations around the globe. But at the other extreme, an energy giant like Valero is able to generate $76 billion of annual revenue with just 0.4% of the employees of Walmart.

It raises the question: which types of companies make the most revenue per employee, and why?

Revenue per head

Today’s chart uses data on companies in the S&P 500 Index courtesy of analytics platform Craft.co.

Instead of plotting the information for all 500 companies, we focused on two groups of firms: (1) energy companies, which tended to skew towards the upper end of revenue per employee ratio, and (2) brands that you will be familiar with, like Netflix, Walmart, Goldman Sachs, Ford, or IBM.

The end result is an astonishing range, with companies making anywhere between <$100,000 per employee (Accenture, McDonald's, Starbucks, Marriott) all the way to >$7 million per employee (Valero Energy).

Industry averages

Here’s a look at this same data expressed as averages at an industry level, based on the sub-sectors that make up the S&P 500:

Rank Sector Avg. Revenue Per Employee #1 Energy $1.79 million #2 Healthcare $0.89 million #3 Utilities $0.81 million #4 Consumer Staples $0.70 million #5 Financials $0.65 million #6 Telecommunications $0.61 million #7 Materials $0.60 million #8 Tech $0.48 million #9 Consumer Discretionary $0.42 million #10 Industrials $0.32 million

Note: this analysis excludes real estate companies

Interestingly, there is even a wide variance between sectors. Oil and gas companies make at least twice as much revenue per employee than the companies in all other sectors, while healthcare and utilities companies also have high ratios as well.

There is a plausible explanation for this large discrepancy, and it has to do with the cost of doing business.

Oil and gas companies have to spend billions of dollars on capital expenditures to build and maintain plants and rigs, while paying extra taxes and royalties. Healthcare companies have to spend a lot on R&D to stay competitive, while utilities must maintain vast amounts of infrastructure. At the same time, all of these sectors generally hire very specialized employees like engineers or scientists, which cost more than average.