Digital marketing agency iCrossing has bought Proxicom, a US web development firm that has created sites for firms including Toyota, Epson and Dupont.

The acquisition will make iCrossing the largest private global digital agency, with 550 employees in the US and UK.

According to iCrossing board member Ren Riley:

“With this acquisition, iCrossing leaps to the head of the pack. Proxicom’s Web expertise, combined with iCrossing’s vision and track record in digital marketing puts the company in an ideal position to not only serve the current requirements of the Fortune 500, but also to be a defining force in the future of digital marketing.” 

Earlier this year, iCrossing acquired UK search marketing agency Spannerworks in a deal worth more than £10m. It has also bought paid search agency Newgate Internet and online marketing firm Sharp Analytics this year.

The company started out as a search marketing agency but now offers a broader range of services, including analytics and market research.

Last week, iCrossing raised $62m (£30.6m) in funding in a round led by Goldman Sachs, and also featuring previous investors Oak Investment Partners, RRE Ventures and StarVest Partners. The company has raised a total of $110m (£54.3m) so far.