Amazon warehouse 2008 2
A worker sorts packages at an Amazon warehouse. Reuters

A former (NASDAQ:AMZN) contract worker recently berated CEO Jeff Bezos in an open letter, criticizing the company’s temp-hiring policies. Steven Barker, who worked on’s X-Ray for TV and Movies, said in his letter that the company has a policy of hiring temp contract workers who are let go after 11 months to save on benefits like medical coverage and paid vacation days.

Even so, ranks only second among Fortune 500 companies with the highest employee turnover rates, according to a special report by Payscale titled “Companies with the Most & Least Loyal Employees.”

With most new hires quitting after just 9-and-a-half months, the company with the least loyal employees is Massachusetts Mutual Life Insurance Company. Also among the top 20 companies with high employee turnover are Google, Inc (NASDAQ:GOOG) and Berkshire Hathaway, Inc (NYSE:BRK.A).

A high employee turnover rate isn’t always because the company isn’t a good one to work for. When workers are willing to hop from job to job, it is usually an indicator of an improving job market, Payscale’s lead economist Katie Bardaro said.

"Workers might be job-hopping more than before. This means that the industry is hot and the economy is improving," she told Business Insider. "Some of the firms on [the high turnover] list are there, because they're a hot market."

Here is a chart of the 20 companies with the least loyal employees, as ranked by Payscale.

Here is a chart of the twenty companies with the most loyal employees, as ranked by Payscale. Please note that in this chart "median tenure" data is not on the same scale as the chart pictured above.

Here's the full list of Fortune 500 companies, ordered by median employee tenure, based on data from Payscale.