Porsche has rejected Volkswagen AG's bid to take a 49 percent stake in the sports carmaker, a company spokesman said Monday.
Porsche Automobil Holding SE spokesman Albrecht Bamler said the offer by VW "is not a viable option."
According to Bamler, Porsche board chairman Wolfgang Porsche received the offer in a letter by courier last week. But the company's CEO Wendelin Wiedeking and management board were not informed.
"Without the management board, nothing goes here," Bamler said.
Porsche holds a roughly 51 percent stake in Volkswagen, but ran up hefty debts in accumulating that holding and is now seeking a merger with the larger company. Exactly how that is to happen remains unclear.
German weekly Der Spiegel reported the VW offer was worth $4.2-$5.6 billion, which would have helped Porsche pay off it debts, racked up in its attempt to take over VW.
Bamler said, however, that for VW to take a stake in Porsche, the Wolfsburg-based automaker would have to take out credit worth $15.15 billion.
Porsche, based in Stuttgart, confirmed earlier this month it has been holding talks with a Qatar state investment fund, the Qatar Investment Authority, on a possible investment.