WPP, the media titan headed by Sir Martin Sorrell, has already made its fourth acquisition of 2012 with the purchase of a majority equity stake in Finnish communications agency Viestintätoimisto Pohjoisranta Oy (Pohjoisranta)The Helsinki-based firm has been an exclusive affiliate partner in Finland to WPP's public relations and public affairs division, Burson-Marsteller, since 2006. It will now join the WPP network as Pohjoisranta Burson-Marsteller.Pohjoisranta, which employs 40 people, generated €5.1 in revenue in 2011, with gross assets at the end of the year of €1.8m. "This acquisition continues WPP's strategy of investing in important markets and sectors. WPP businesses in Scandinavia, including associates, generate revenues of over US$500 million and employ nearly 3000 people," WPP said.No financial information related to the transaction was given, nor was any information regarding the size of the "majority stake".