Sauber has not paid the February salaries of its Formula 1 staff in full because of cashflow problems.
The Swiss team is said to be in the advanced stages of securing a title sponsor, but an agreement has yet to be signed.
Autosport understands its current portfolio of sponsors are up to date with their payments to the team.
It comes after Sauber, along with Force India and Manor, asked Bernie Ecclestone in November for an advance on their championship payments.
With intense work on production to get the cars ready in time for Melbourne, this time of year is particularly financially challenging for teams.
Despite the situation, it is believed Sauber is on schedule to compete in the season-opening Australian Grand Prix later this month.