Minneapolis-based Norwest Equity Partners has sold Amcom Software, Inc., for $163.3 million in cash.

Norwest, a middle-market equity investment firm, sold its portfolio company to Alexandria, Virginia-based USA Mobility, Inc.-which provides wireless messaging and communications services.

Norwest and venture capital firm Split Rock Partners, which has an Eden Prairie office, jointly invested in Eden Prairie-headquartered Amcom in December 2009.

Amcom provides mission-critical communications software-and USA Mobility said that Amcom will help it meet the needs of organizations as they communicate using an ever-increasing array of methods and devices.

“This acquisition is about combining two leaders in mission-critical communications,” USA Mobility President and CEO Vincent D. Kelly said in a statement. “USA Mobility's three primary core market segments of health care, government, and large enterprise are exactly aligned with Amcom's customer-segment focus.”

Amcom's software is used in a variety of applications, including giving heart attack patients life-saving treatment sooner, alerting nurses about urgent patient needs via mobile devices, helping call center operators process requests more easily, and helping emergency response teams quickly locate 911 callers.

According to USA Mobility, Amcom's unaudited revenues totaled about $51 million in 2010-up 19 percent from 2009.

Amcom has six offices across the world, all of which will remain open. USA Mobility plans to retain all Amcom employees as well-including managers.

Norwest Principal Tom Schauerman said in a statement that the Amcom management team has “done a great job executing on the growth strategy and [is] well-positioned for continued momentum and performance with USA Mobility.”

Norwest is a private equity firm that focuses on building companies into industry leaders. It manages $4.6 billion of capital through a series of equity and mezzanine funds. The firm is currently investing in NEP IX, a $1.2 billion fund.

Norwest typically invests between $10 million and $50 million. Its investments span a wide range of industries, including distribution, manufacturing, health care, and consumer products.