Four Iowa-based companies are featured on the America’s Best Employers 2015 list released Wednesday by Forbes magazine. The list includes 500 companies and nonprofit organizations in 25 industries. Google Inc. was the overall best employer, based on responses from more than 20,000 American workers surveyed. Among Iowa companies that were included, University of Iowa Hospitals and Clinics, which employs 9,000 people in Iowa City, was ranked No. 12. The survey asked employees how likely they would be to recommend their employer to someone else, using a scale of zero to 10. They were also asked to rank other employers in their industry. Other Iowa-based companies on the list included Principal Financial Group Inc. (63rd), Rockwell Collins Inc. (96th) and Hy-Vee Inc. (273rd).