Calabrio, a Minneapolis-based maker of customer analytics software for retailers and other businesses, has received a second major investment from KKR, the giant New York investment firm that bought a controlling stake in the company two years ago.

Terms of the investment, which closed earlier this month, were not disclosed. KKR reportedly spent $200 million in August 2016 when it took the majority stake in the company.

Calabrio offers a variety of cloud-based software services that help companies identify what works when sales and service representatives are talking with customers and prospective customers on the phone, via e-mail and online.

Calabrio was a 2007 spinoff from Spanlink Communications, a call-center firm that's now a unit of ConvergeOne in Eagan. As it started to grow, executives changed the company's development to focus on cloud-based services that let companies operate centers with its technology over the internet.

That allowed Calabrio to offer services, such as the recording and long-term storage of voice calls between customers and service representatives, to businesses that wouldn't have wanted to build them on their own.

"We have seen a rapid shift from on-premises to cloud-based deployments," Tom Goodmanson, Calabrio's chief executive, said in a statement referring to firms that no longer need to house data storage and other systems to run call centers.

"Having a partner like KKR to back this growth has been a driver of our success," he added.

More recently, Calabrio has integrated its analytics software with larger firms that provide contact centers as a service to businesses, including Amazon and Cisco.