UK ad-holding company WPP Group, fresh off its takeover of audience researcher TNS, has sold its 50 percent stake in TV researcher AGB Nielsen Media Research to Nielsen. In return, Nielsen will transfer to WPP the assets of ad-pricing researcher SRDS and health-care media-planning data unit PERQ/HCI. Nielsen will also give over its 11 percent share in several subsidiaries belonging to Brazilian media research firm IBOPE Group.  WPP already holds a 31 percent stake in IBOPE. These assets will be added to The Kantar Group, WPP’s information, insight and consultancy division. For the past year, WPP has been ramping up its investments in emerging markets like Brazil, so aside from unloading its stake in a TV researcher it doesn’t need after acquiring TNS, the move fits with WPP’s interest in adding assets in Latin America. Release