Mar.24 (GMM) Mercedes may have withheld its signature from the new 2013 Concorde Agreement because of a disagreement about bonus money.
That is the claim of Germany's authoritative Auto Motor und Sport, hot on the heels of Bernie Ecclestone's news on Saturday that the "majority" of teams - including grandees Ferrari, Red Bull and McLaren - have now agreed terms.
The German report said Mercedes has recently been pushing for additional money on the basis of the team's historical lineage.
Auto Motor und Sport said teams are not only paid according to their recent achievements, but also their historical success and years of participation.
Before it was Mercedes, the Brackley based entrant was known as Brawn GP, Honda, BAR and Tyrrell.
Tyrrell made its Grand Prix debut in 1968, going on to win three world championships with Sir Jackie Stewart.
It is also believed Williams is yet to sign the 2013 Concorde.