Irvine-based telecommunications company Horizon Communications Technologies has sold a “significant” ownership stake to Solis Capital Partners LLC, a private equity firm in Newport Beach.

The purchase price and percentage of ownership were undisclosed.

Horizon Chief Executive Mike DeGraw, who bought the company in 2010 after working in the telecom industry for about two decades, said he remains a “significant shareholder” under terms of the deal.

Horizon for several years has provided cabling services for office buildings, including those owned by Newport Beach-based Irvine Company, which is the largest office landlord in Orange County and has acquired substantial holdings in the San Diego and Silicon Valley markets in recent years.

DeGraw brought additional business for Horizon, which now gets a substantial portion of its revenue from installing wireless networks at sports stadiums, as well as designing and building infrastructure for large data centers.

Horizon’s list of past and ongoing projects includes work for Twitter Inc. and Salesforce.com Inc., both based in San Francisco. The company also has worked on the Honda Center in Anaheim and the Chase Field in Phoenix. It’s currently halfway through a project at Dodger Stadium in Los Angeles.

“The stadiums part is about 70% of our business,” DeGraw said. “Data centers are big as well, but just not the sheer size and scope of putting in a network in a 60,000-seat stadium.”

Horizon has annual revenue of about $16.5 million and about 100 employees, according to DeGraw—“big changes” compared with when he bought the struggling company.

“There wasn’t a whole lot going on at the time,” he said. “The company really just had a riser-management contract with the Irvine Company. By riser-management I mean the telecommunications infrastructure that runs vertically in a building. We still value that business and maintain it. But the problem was, in 2008, 2009, nobody was moving.”

DeGraw oversaw a shift in company culture and helped it grow about 50% the first year after he took over.

It helped that he was able to bring in relationships built up from his previous stints. He most recently served as part of executive management at Leucadia National Corp., a New York City-based holding company that operates through its investment banking, energy and telecommunications arms, among others.

DeGraw ran several of Leucadia’s operating companies, including WilTel Communications Group LLC, which was acquired by Broomfield, Colo.-based Level 3 Communications Inc. in 2005 for nearly $800 million. He also launched and managed TeleBarbados Inc., a local phone company in Barbados.