Dr Helmut Marko thinks "a lot is happening" behind the scenes at Mercedes.
The Red Bull chief's former charge Sebastian Vettel, who will leave Ferrari at the end of the year, is being linked with a move to Mercedes for 2021.
Others say Vettel could go to 'Aston Martin' - which according to speculation may in fact be the works Mercedes team's new identity for 2021.
"Let's wait and see what developments are going on at Mercedes," Marko told Osterreich newspaper. "I hear that a lot is happening there in terms of personnel."
Indeed, team boss Toto Wolff has allied with Racing Point owner Lawrence Stroll in buying Aston Martin shares. It is rumoured that the pair could swap some of these shares in exchange for control of the Mercedes team.
When asked if Mercedes will be in F1 beyond 2021, Marko answered: "If they're still there, that's fine. We will want to beat them. If they are not, it will be a different team."
As for whether the Brackley based team will merge with Aston Martin, the Austrian added: "I don't want to take part in this speculation."