"The negotiations are in the final stretch," a Porsche spokesman told AFP. "The negotiations are advancing well, on the basis of a positive examination of the accounts."
Qatar has said it is interested in a direct stake in Porsche, though another option would be for the Gulf state to buy options in Volkswagen shares held by Porsche.
The owners of Porsche, the Porsche and Piech families, could meet in the coming days to validate an agreement with Qatar. One infuential member, Ferdinand Piech, has said in the past that he opposes selling Porsche shares to Qatar however.
Piech is also head of the supervisory board at Volkswagen, in which Porsche owns a stake of 51 percent, and he would prefer to see VW buy the luxury sports car maker in a reverse takeover.
Porsche accumulated some €9 billion ($12.6 billion) in debt trying to increase its VW holding to 75 percent. It has asked the German government for a credit of €1.75 billion, but officials have declined to approve the request.