Apple CEO Tim Cook drops from 8th to 53rd in Glassdoor rankings

Apple's Tim Cook has slipped from 8th to 53rd place in Glassdoor's annual CEO rankings for large U.S. businesses, based on anonymous reviews left by the company's workers.

Cook nevertheless scored a 93 percent approval rating, Glassdoor said. In 2016 Cook managed 96 percent, helping to elevate him from 10th place in 2015, and 18th in 2013 and 2014.

The top six executives this year all achieved a 99 percent rating. These included Clorox's Benno Dorer, World Wide Technology's Jim Kavanaugh, Boston Scientific's Michael Mahoney, Memorial Sloan Kettering's Craig Thompson, Fast Enterprises' Martin Rankin, and Nvidia's Jen-Hsun Huang.

Some other notable technology CEOs on the list are SpaceX's Elon Musk (#8), Facebook's Mark Zuckerberg (#10), and Microsoft's Satya Nadella (#29).

It's not clear what led to Cook's fall, although simply being in the top 100 puts him well above the 67 percent average CEO rating for companies on Glassdoor. Some general complaints about Apple are a lack of work-life balance, and difficulty being promoted, particularly at retail.

Outside of the company, Cook has sometimes been accused of failing to innovate as much as his predecessor, Steve Jobs. Mac, iPhone, and iPad design has been mostly evolutionary under his CEO tenure, and the only major new category launch has been the Apple Watch. The next — the Siri-based HomePod — is due this December.