The sale had been expected to be completed as soon as this week. 'Penske Automotive Group ... has decided to terminate discussions with General Motors to acquire Saturn,' GM Chief Executive Fritz Henderson said in a statement. As a result, 'we will be winding down the Saturn brand and dealership network.' The news is a blow to GM, which had made selling three of its brands, along with shutting Pontiac, a key component of its post-bankruptcy restructuring efforts. GM has come to final terms on a deal to sell Saab to a Swedish maker of exotic sports cars, but it has not finalized the sale of Hummer to a Chinese manufacturer. Instead of selling Saturn, GM will close the brand altogether. It said Wednesday that its Saturn dealers already had signed a 'wind-down agreement.' Under terms of a similar agreement signed by some other GM dealers, all new-car sales operations must cease by late 2010. Penske, which operates a chain of dealerships around the United States, emerged as a buyer for Saturn in early June, beating out several other interested parties, including an Oklahoma-based private wealth fund. The company, which currently distributes the SmartCar in the U.S., planned to continue selling GM-made Saturns at dealerships for the next year or two, by which time it planned to have lined up a foreign supplier to provide new cars badged as Saturns. Although it had found a suitable manufacturer to produce the vehicles, 'that agreement was rejected by that manufacturer's board of directors,' Penske said in a statement. 'Without that agreement, the company has determined that the risks and uncertainties related to the availability of future products prohibit the company from moving forward with this transaction.' There are roughly 350 Saturn dealers. Through the first eight months of this year, they sold 57,223 new vehicles, down 60 percent from the year-earlier period. 