ECS Federal LLC announced Wednesday that it has signed a final agreement to be acquired by On Assignment Inc. for $775 million. On Assignment’s stock surged after the announcement.

On Assignment, the Calabasas IT and professional services provider, acquired ECS through Roy Kapani, the company’s majority owner and founder.

“We are excited to have George Wilson (the chief executive) and his entire ECS team join with us,” said Peter Dameris, chief executive officer of On Assignment in a statement. “We believe that ECS is well positioned to achieve high single-digit growth in 2018.”

ECS of Fairfax, Va., is one of the largest privately-held government services contractors delivering artificial intelligence, cyber security, cloud computing and advanced science and engineering services to commercial and government enterprises,

Post-acquisition, ECS will be part of a publicly traded organization with combined revenues of $3.2 billion and $379 million in earnings before interest, taxes, depreciation and amortization. It also will have more than 24,000 professionals.

It will give ECS access to digital, creative and life sciences and open On Assignment’s customer market to ECS.

The transaction is expected to close April 2, the same day On Assignment will change its name to ASGN Inc.

On Assignment’s stock on Wednesday jumped $7.69, or more than 11 percent, to $76.57 on the New York Stock Exchange.