GM, Chrysler and Ford in turmoil
GM owns Saab, Vauxhall, Cadillac, Chevrolet, Corvette and Hummer, while Chrysler also owns Jeep and Dodge.
The two US-based companies are in talks to join forces, in an effort to save money by sharing administration and infrastructure costs, as well as developing cars on the same platforms in the future.
Both are losing substantial amounts of money at present, and the current decline in car sales in the face of global economic gloom and rising environmental awareness has further hit sales.
While talks are still ongoing, any sale would not affect the rights of the owners of cars built by either manufacturer.
Ford and Mazda
Ford is also reported to be considering selling its stake in Mazda.
Ford owns one-third of Mazda, which is profitable and reported to be worth around $1.3 billion (about £750 million).
Ford would use the money raised to help fund its troubled car sales operations in America, which have lost almost $24 billion since 2005.