SFN Group Inc. (NYSE: SFN) shares shot up 51% to $13.93. Late Wednesday, the staffing-services provider and Dutch company Randstad Holding NV said the latter would acquire the former for about $770 million. Volume on SFN was 12.4 million shares, contrasted with a daily average of less than 570,000.

As a result of the acquisition, announced in a news release Wednesday, Randstad will become the third-largest HR services provider in North America, doubling its presence in the U.S. and reinforcing its leading position in Canada. Randstad and SFN Group have a comparable service offering in North America and a complementary geographic coverage, which creates a unique strategic fit.

In North America, the combination will have revenues of $4.6 billion (pro forma, LTM March 31, 2011) of which 39% in Professionals, 52% in Staffing and 9% in HR Solutions (Payrolling, Managed Services and Recruitment Process Outsourcing).

This represents under 5% of the highly fragmented North American HR Services market. The combination will have over 5,000 employees and operate from over 1,000 outlets. As a result of the transaction, the Randstad Group will have combined revenues of approximately $22 billion/ euro 17 billion (pro forma, LTM March 31, 2011).

SFN CEO Roy Krause was quoted in the release as saying, “The executive management and I are confident that the combination of our two companies is a strong strategic fit that will not only deliver expanded service offerings for our clients in North America, but also creates opportunities to service them on a global basis.”

“Both companies have complementary cultures and values which will provide growth opportunities for our staff associates.” Krause concluded.