SAS and Duke University are two of the nation’s top large company employers in the U.S., according to a new report from Forbes magazine.

SAS placed sixth and Duke 14th, based on a survey of employees.

UNC-Chapel Hill also made the list, coming in 40th.

In a report on mid-sized employers, RTI International placed sixth.

Marathon topped the large-firm list followed by Google.

Cary-based SAS is a regularly recognized company for its treatment of employees.

How was the list compiled?

“Working with online statistics provider Statista, Forbes asked more than 30,000 U.S. workers employed by companies with more than 5,000 staff members to determine, on a scale of zero to 10, how likely they were to recommend their employer to someone else,” Forbes says.

“Further, how did they feel about the other employers in their industry?”

See the full large-company list at:

http://www.forbes.com/best-employers/list/#tab:rank