A long driver ’silly season’ is finally coming to an end, according to Haas boss Gunther Steiner.
While it appears there are only a few seats left for 2017, vacancies at Force India, Renault, Manor and Sauber remain open.
Williams will confirm Valtteri Bottas and Lance Stroll on Thursday.
And Auto Motor und Sport reports that Esteban Gutierrez is leaving Haas, with Kevin Magnussen and Pascal Wehrlein on the shortlist to replace him.
"Everyone’s waiting to see what the others do," said Steiner.
"But someone has to decide now and I think it will be by Brazil. It’s getting tight," he added.
"To conclude deals after the last race in Abu Dhabi is always difficult because people go on holiday," said Steiner.
Force India has the most competitive vacant seat on offer, and Sergio Perez is urging the team to choose the fastest possible option to be his teammate.
"It would be ideal to have two strong drivers," he told France’s Auto Hebdo.
"With Nico (Hulkenberg) we have strong internal competition and this in large part explains the success of the team," added Perez.