Perez arrived at the team on the back of the Swiss outfit's tie-up with Telmex, and had been viewed as an integral part of the company's F1 plans.
However, despite speculation that Perez's move to McLaren could lead to Telmex switching its allegiance, Sauber says there is no doubt about the sponsor's commitment to the Swiss outfit.
Sauber CEO Monisha Kaltenborn said that the company had been informed of Telmex's commitment when it was told that Perez would be moving to McLaren.
"We were informed by Telmex about this change, and Telmex also told us that for them they have a long-term project with Sauber, and this will not be affected by Sergio leaving the team," said Kaltenborn.
She added: "They have an overall vision regarding motorsports - which is not only their racing school. They want to establish motorsport more in that part of the world.
"They also use F1 as a marketing platform with the enormous brands that they have, so I think they really have a proper big vision with motorsport involvement in that area. So it is a bigger picture, and we fit in very well with what we have done with their drivers."