The task covers the Prudential, Egg and M&G Investments brands. MediaCom was already the incumbent on the £12 million Egg business, but it will now add the £8 million Prudential brief, along with the M&G Investments account.
The decision follows a shoot-out between Media-Com and ZenithOptimedia. Universal McCann and the Prudential incumbent, Omnicom's PHD Group, were both knocked out of the pitch at an earlier stage.
The review was overseen by Prudential's chief marketing officer, Alison Wright. She was promoted to the group role from Egg, following the departure of the Prudential UK and Europe marketing director, Roger Ramsden, earlier this year.
Wright was previously the chief marketing officer for the online bank Egg.
Before that, he was the managing director of Manning Gottlieb OMD.
The decision to consolidate the media businesses came after the Prudential Group bought back the 22 per cent of Egg that it did not own and, in January, appointed Nick Prettejohn as its UK chief executive.
The Prudential Group and MediaCom both declined to comment.