Only 3 companies have been rated 'best places to work' for 10 years, and they have a few things in common

• Glassdoor published a list of the best companies of 2018 based on anonymous employee reviews.

• Business Insider looked into which companies have made its list - which features 100 companies annually - since its inception 10 years ago.

• Bain & Company, Google, and Apple were the only three companies to have made the list every year.

Glassdoor's list of the 100 best companies of 2018 saw plenty of newcomers - 40, to be exact.

But only three companies have managed to make the job site's list every year since its launch ten years ago. And they're all big names: Bain & Company, Google, and Apple.

Bain & Company and Google topped the list, snagging the second and fifth spots, respectively. Apple came in at 84.

Business Insider decided to take a look at some of Glassdoor's analytics to figure out what reviewers love about these three companies.

We found that all three are led by widely adored CEOs, typically hold moderately tricky interviews, and feature top perks like generous paid time off policies, health insurance, and 401K plans.

Here's a closer look at how the three companies stack up: