The deal for the 26-story, 310,541 square foot building is scheduled to close Wednesday for around $60 million.
If the deal goes through it will mark the first sale of a downtown office building this year.
It also could represent the first time a Mexican investor has made a large real estate purchase in the Chicago area.
No one from the company or the Chicago real estate community was willing to comment on the potential sale. But the company’s lawyer recently formed a group called 303 Madison Chicago LLC, which is a move that would seem to signal a tie-in to that property.