AMI agreed to buy Denver-based PSL Healthcare.

The agreement to acquire the company and its three Denver-area hospitals and affiliated activities for $178 million in cash will be the largest merger ever between an investor-owned company and a nonprofit hospital chain, American Medical International officials said. The deal would add three hospitals, with a total of 1,037 beds, to AMI’s hospital portfolio: Presbyterian Denver, St. Luke’s and Presbyterian Aurora. The Los Angeles-based chain would also acquire a number of affiliated facilities, all in Colorado.