While four may sound like a small number, it’s actually disproportionately high: Women make up just 4% of Fortune 500 CEOs, but account for 8% of Glassdoor’s list, which includes companies with more than 1,000 employees.

Here’s who made the cut:

1. Lynsi Snyder, president of In-N-Out Burger

At #17, Snyder is the highest-ranking woman on Glassdoor’s list. The 34-year-old heiress to the In-N-Out fortune is notoriously media-shy, but celebrity doesn’t seem to matter to her employees, 95% of whom said they approved of her leadership over the past 12 months. While Snyder’s title today is president, she will take full ownership of the company when she turns 35 next May.

2. Lesa Francis, CEO, president, and director of Staffmark

Francis, who heads commercial employment agency Staffmark, ranks #28 on the list overall. During her decade-long tenure at the company, it has doubled in size to become one of the largest staffing companies in the U.S., according to the company website. Perhaps that explains her 94% approval rating.

3. Pam Nicholson, CEO, Enterprise Holdings

In 2013, Nicholson became both the first woman and the first non-member of the founding Taylor family to be named CEO of Enterprise. Today, the head of the largest car rental company in the world enjoys a 94% approval rating and ranks #28 on the list of 50 most beloved CEOs. She is also No. 20 on Fortune’s list of the Most Powerful Women.

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4. Cathy Engelbert, CEO of Deloitte LLP

Engelbert, who appeared on Fortune‘s list of Most Powerful Women for the first time last year, made history last March when she became the first woman to be named CEO of a Big Four firm in the U.S. A little more than a year into the job, the 30-year Deloitte veteran has a 93% approval rating and appears at #41 on Glassdoor’s list.