General Motors would need to find $6.1 billion (£3.7bn) if it wants to keep hold of Vauxhall and Opel rather than sell them off.
The figure was presented to GM's board, which is meeting today to try and decide what to do with its European operations, by its financial advisors, KPMG, according to the Reuters news agency.
Around two-thirds of the money would be needed to keep Vauxhall and Opel running, while the other third would be payable to the German government, which has given a bridging loan to keep the company running during the current financial crisis.
GM must decide between trying to hold on to its European operations, or selling to either Magna, which is the German government's preferred bidder, or RHJ International, which is GM's preferred bidder.
Although a decision is possible this week, some reports have indicated GM may wait until next month before deciding what to do.