Bob Bechek speaking at the Oxford Union in Oxford, Britain on March 12, 2015 (Rex Features via AP Images)

Facebook founder and CEO Mark Zuckerberg. LinkedIn CEO Jeff Weiner. Google (now Alphabet) co-founder and chief executive Larry Page.

For the past three years, these well-known Silicon Valley CEOs topped Glassdoor's annual list of the chief executives with the highest anonymous approval ratings from employees on the career web site. But this year, the highest rated CEO is much less well known, at least outside top executive suites.

Bob Bechek, the worldwide managing director of Bain & Company, the management consulting firm, was ranked highest on this year's list. A 30-year veteran of the firm who led a robotics company before joining Bain, Bechek took over its leadership in 2012. Current and former Bain employees who filled out reviews on Glassdoor's site over the past year gave him an approval rating of 99 percent.

He squeaked into the top spot above two other CEOs who also had 99 percent approval ratings: Another relative unknown, Ultimate Software CEO Scott Scherr, and another leader of a major management consulting firm, McKinsey & Co. CEO Dominic Barton.

Glassdoor's career trends analyst, Scott Dobroski, said the close finish had to be decided by looking beyond the thousandth decimal point. "The differences in these ratings are very, very miniscule," he said.

The rest of the top 10 included more well-known names, such as Zuckerberg (No. 4), Salesforce CEO Marc Benioff (No. 6), who has been an outspoken advocate for gay rights, and Apple CEO Tim Cook (No. 8). Google's new CEO, Sundhar Pichai, came in at No. 7.

While the list names the 50 top-rated CEOs by employees, in reality there is little difference between the approval ratings of Bain's Bechek and Sephora CEO Calvin McDonald, the 50th-ranked CEO, who had a 92 percent approval rating. The overall scores have improved markedly in recent years, with the 50th-ranked CEO seeing an approval rating of 78 percent in 2014, 88 percent last year, and 92 percent this year.

Glassdoor's Dobroski says that's likely a result of what has been -- despite last week's gloomier jobs report -- a strong labor market. "It's natural to see those numbers go up when you look at the themes in the reviews," he said. "It's been a job seeker's market. Employees are feeling good in their jobs right now, they're more happy with senior leaders, and they're not hearing about as many job cuts."

Is it possible that as the annual list hits its fourth year, more companies could be filling the ballot box with positive votes about their CEOs? (The approval rating is set by employees answering a simple question about whether they do or don't approve of the CEO; a company's CEO can only be considered for the list if there it has at least 100 reviews and at least an overall 3.0 employee satisfaction score.) Dobroski says the Glassdoor employs both technological and human methods to prevent any gaming of the list's results, but would not provide much more detail about its processes, for fear that "it would give away how someone could game it."

Glassdoor's community guidelines do prohibit incentivizing reviews, Dobroski says, and its "content services management team" checks reviews for fraud. Companies or CEOs may be subject to being manually excluded from the list if there is abuse of the reviews, which it determines on a case-by-case basis. "We have robust technology and human touch reviews in place," Dobroski said.

This year's list includes four female leaders -- the most so far -- In-N-Out Burger president Lynsi Snyder, Staffmark CEO Lesa Francis, Enterprise Holdings CEO Pamela Nicholson and Deloitte CEO Cathy Engelbert. Other familiar corporate names include Nike's Mark Parker at No. 29, Goldman Sachs' Lloyd Blankfein at No. 33, and Costco Wholesale's Craig Jelinek at No. 46.

So what gives Bechek such a high approval rating? According to Glassdoor, one employee said in a review about the firm's senior management that "someone told me before I joined Bain, 'The best thing about Bain is how Bain runs Bain,' " though doesn't comment specifically on Bechek. He has received little press, but in a recent Q&A by the MBA site Poets & Quants, he's described as being known as modest with a "self-deprecating wit" and calls empathy and perseverance the most essential qualities for a successful career.

In a speech last year at the Oxford Union, the prestigious debating society, he described saying 'no' a couple of times before taking the top job at Bain. "I didn't seek this role," he says. Even so, many employees apparently think he does a good job in it.

Read also:

The best CEOs, according to employees

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