WPP, the FTSE 100 advertising and media giant led by Sir Martin Sorrell, has bought a majority stake in German digital media agency k102, as it continues to expand its digital capabilities.k102, based in Dusseldorf, was founded in 2006 and generated revenues of €1.3m in 2011 with gross assets at the end of December of €1.2m. It has worked alongside WPP's global marketing communications division Grey since January 2010 and has a client list including Deichmann, Transparo, MBT, Gard and Toshiba."This investment continues WPP's strategy of developing its services in fast-growing and important markets and sectors and strengthening its digital capabilities," WPP said on Monday morning.WPP generated $4.8bn of revenues in digital last year, representing around 30% of group sales. The firm has set a target of 35-40% of revenue to be derived from digital in the next five years.