Briton Murray and Brazilian Soares are top of the Edberg/Jarryd Group and provisionally leapfrogged Nicolas Mahut and Pierre-Hugues Herbert in the world rankings.
The French pair will be in front again if they win their final group match but, having been defeated in their first two outings, they cannot reach the last four at the O2 Arena.
Murray and Soares, who take on Spanish duo Feliciano Lopez and Marc Lopez or South African Raveen Klaasen and American Rajeev Ram on Saturday, will finish the year at the top of the rankings if Mahut and Herbert lose their last group match.
