Perez joined Sauber for 2011 on the back of the team's tie-up with Telmex, and his presence within the team was viewed as being critical in their commitment.
With Perez having been confirmed as Lewis Hamilton's replacement from the start of 2013, there had been an expectation the Mexican firm would end their deal with Sauber.
But Sauber chief executive Monisha Kaltenborn has confirmed that Telmex chairman and chief executive Carlos Slim, ranked as the richest man in the world, has committed himself to the Swiss team.
Slim's links with Sauber also include the Escuderia Telmex initiative, designed to promote the brightest Mexican driving talent.
And Kaltenborn said: "The prospect for next season is good. We are very confident we will be around, for hopefully more years.
"As for the sponsors, we know that Telmex, that is Mr Slim, has also publicly stated that his project with Sauber, regarding the Escuderia Telmex, is a long-term project, so it will not be affected by Sergio's leaving the team."
GP2 racer Esteban Gutierrez, another Mexican, is among the favourites to replace Perez, but Kaltenborn would not be drawn on whether they were close to concluding a deal.
She said: "As we have been saying before, we will announce our driver line-up for next year in due course and we're not in a hurry to do that.
"We still have things to sort out. Regarding Esteban, he's been with the team since his Formula BMW days and he has been our reserve and test driver for the past two years.
"But it is something totally independent from Sergio's leaving and we don't really want to mix them together. We'll announce whatever we have to in due course."
But Kaltenborn did confirm the team had not held talks with Michael Schumacher, who announced his retirement yesterday.
Prior to the German's decision, he had been linked with a drive at Sauber, who he raced sportscars for in the late 1980s and early 1990s.
She said: "We were never in negotiations with him."