Connextions—a subsidiary of Minnetonka-based UnitedHealth Group, Inc.’s Optum health services business—on Tuesday announced plans to open a 550-employee call center this month in Centennial, Colorado.

Orlando-based Connextions enrolls and retains new customers in health insurance programs for Optum and fields calls from customers to help pair them with health plans.

The new 45,000-square-foot office is Connextion’s eighth call center in the United States; it cost $4 million, UnitedHealth Group said.

The company has already begun recruiting in the Denver area for 500 licensed and non-licensed insurance agents. Employees will earn an average of $30,000 to $40,000 a year, UnitedHealth Group said.

Connextions and Optum already have a presence in Colorado: Connextions runs an “innovation center” outside of Boulder that employs 40 people, and Optum employs nearly 600 people in the state.

“Connextions is committed to helping consumers navigate the complex, important, and very personal decisions related to their health care,” Connextions President Steve Auerbach said in a statement. “We are very excited about delivering that service from Colorado.”

UnitedHealth Group is Minnesota’s largest public company based on revenue, which totaled $101.9 billion in 2011.

Like what you just read? To receive business news directly in your inbox each Tuesday and Thursday, sign up for our free e-newsletter, Briefcase, and be sure to join the conversation by commenting below.