Liberty Media is pressing ahead with its August 12 deadline for the finalisation of the 2021 Concorde Agreement.
While Cyril Abiteboul says "95 percent of the teams are agreed" about the terms of the next binding commercial deal, Mercedes boss Toto Wolff says he is not ready to sign.
He alleges Mercedes is the "biggest victim" in terms of how the prize money will be divvied up.
"There are a bunch of open topics for us that are legal, commercial and sporting and in our point of view I don't feel ready to sign," said Wolff.
However, Liberty Media set an August 12 deadline - Wednesday - some time ago and a source told Auto Motor und Sport that the F1 owner is pushing ahead.
"We have discussed all the issues for long enough and will not allow any further delay," the source said.
Wolff, though, says it is up to Liberty to break the deadlock.
"If you are willing to sit at a table, address the critical topics, discuss them and come to a compromise outcome, then I think it can go pretty fast," he said. "But I haven't seen that approach."
