Atomic PR is being merged into Grayling effective Jan. 1, three years following the British firm's acquisition of the San Francisco-headquartered tech/social media firm.

Atomic co-founder CEO Andy Getsey takes on the executive VP title, while fellow founder James Hannon will become chief data strategist. They will co-head Grayling's U.S. technology practice.

Pete Pedersen, CEO of Grayling, believes the merger provides the Huntsworth unit "additional U.S. critical mass" and "significant expertise in the use of data to guide strategy and creative."

Pedersen told O’Dwyer’s Grayling now has about $45M in U.S. fee income and 300 staffers here. He said Grayling plans to expand its U.S. and Asian presence and bolster its digital offerings.

With the addition of Atomic's six U.S. offices, Grayling will have 10 offices in the U.S. in New York, Washington, Tallahassee, Denver, S.F., Sacramento, Silicon Valley, Los Angeles, Orange County and Silicon Valley.

Grayling consolidated DutkoGrayling PA/government affairs unit in September.