Perion Network has bought digital advertising firm Undertone for $180 million in cash as it continues to expand in providing advertising to brands and publishers, it said.

Israel-based Perion, whose technology helps developers distribute apps and make money off them through advertising, said the acquisition would immediately add to earnings. It creates a combined company with about $350 million in sales in 2015.

Perion will pay $91 million at closing, another $19 million in 18 months and $20 million in 2020. It also entered into a new credit agreement with existing Undertone lenders for $50 million.

Perion shares were up more than 10 percent in New York.

Undertone is expected to have 2015 revenues of $143-$145 million and adjusted earnings before interest, taxes, depreciation and amoirtisation on $21-$23 million, Perion said.

Perion said the acquisition substantially diversifies its revenue base, broadens its product suite with the addition of proprietary formats and enhances its mobile footprint.