Paul Tracy is the reigning Cart champion
Next season's Cart series is under threat, officials announced on Tuesday.
The start date for the series has already been put back from 22 February to 18 April, but the whole season is now in doubt.
Chief financial officer Thomas Carter said a potential purchaser had told him there would not be enough teams entered for a sale to go through.
Open Wheel Racing Series had made a minimum number of participants a condition of the offer to buy Cart.
Carter said Cart's directors were "evaluating available alternatives to the merger, including the possibility of ceasing operations, winding up the company's affairs and liquidating its remaining assets".
OWRS has made a substitute proposal to have Cart file for bankruptcy.
The proposed sale is due for a shareholder vote on 19 December.
Cart has been facing a crisis in recent years as more and more of its top teams and drivers have defected to the rival Indy Racing League series.
Cart has suffered because America's biggest and most prestigious race, the Indianapolis 500, is part of the IRL.
The Indy 500 was part of the Cart series - then called the IndyCar World Series - until Indy boss Tony George set up the IRL in 1996.
George said he wanted to provide a platform for up-and-coming American drivers.
But while he has had some success on that level, the all-oval series has grown to be dominated by former Cart teams.
Many leading figures in US racing believe that the two series should formally join forces, rather than splitting a fan base which is anyway smaller than that of the Nascar Winston Cup stockcar series.
However, despite occasional talks between Cart and the IRL, no agreement has yet been reached.
Many suspect George is simply waiting for Cart to die so he becomes the de facto boss of single-seater racing in the US.
There has been speculation that once that happens, he would allow the IRL to branch out into road-course racing as well as ovals.