Titan Outdoor, JCDecaux, Streetbroadcast and Redbus Outdoor are believed to have submitted bids. However, Media Week understands Clear Channel Outdoor did not make a final bid.
Donaldson Lufkin & Jenrette, the investment bank owned by Credit Suisse Group, has emerged as an outside contender.
Tim Schoonmaker, former chief executive of Emap Radio, is working with DLJ to find media investments in the UK, but would not comment on a possible bid for Primesight.
Meanwhile, a merger between UTV and SMG will now almost certainly go ahead, according to analysts. The two companies confirmed they were back in talks yesterday, 11 December.