Advertising conglomerate WPP has upped its stake in Mindshare South Africa by acquiring Ogilvy South Africa's 50% stake for an undisclosed sum.Mindshare is a media buying and planning operation within South Africa. In 2009 its audited consolidated revenues totalled 53.23m rand, and at the end of 2009 its gross assets were 357.8m rand.Key clients and partners of Mindshare South Africa include Kellogg, KFC, LG, MTN, MultiChoice, Sun International and Unilever.Mindshare will now form part of WPP's GroupM network of companies within South Africa.