"I don't think you can truly compete without having the capabilities of a large car company behind you," said John Wolkonowicz, an independent auto analyst. "There are very few examples of sustained success without it."
A representative at Investment Dar who asked not to be named denied the company is seeking to sell Aston Martin.
Janette Green, director of brand communications at Aston Martin, said Investment Dar isn't considering a sale. Roma Balwani, a Mahindra spokeswoman in Mumbai, declined to comment on speculation.
Toyota's analysis, which was preliminary and carried out less than two months ago, hasn't advanced to a full-blown evaluation, the person familiar with the matter said. Shino Yamada, a Toyota spokeswoman in Tokyo, declined to comment.
Investment Dar has reason to sell its Aston martin stake. The company agreed in February last year to reorganize 1.37 billion dinars ($4.9 billion) of debt after missing payment on an Islamic bond in May 2009. The restructuring is being implemented under Kuwait's Financial Stability Law, enacted by the government in April 2009 to bolster financial institutions hurt by the credit crisis.
Before Investment Dar and Adeem Investment Co. became owners five years ago, Ford had controlled the brand since 1987.
While Aston Martin still gets engines from Ford, it lost access to Ford's other resources after the sale and remains the only global luxury brand that's not part of a larger auto group.
That independence could be a handicap with the auto industry under pressure to develop technologies to improve fuel efficiency. BMW is investing more than 1 billion euros ($1.3 billion) this year on making engines more efficient and developing electric vehicles. That sum exceeds Aston Martin's 2011 revenue of 507 million pounds.
Large carmakers can help niche manufacturers stay competitive by spreading development costs across brands and models. Fiat owns Maserati and Alfa Romeo as well as Ferrari. VW completed the purchase of the Porsche car brand this year, adding the maker of the 911 alongside Audi, Bentley, Lamborghini and Bugatti.
VW uses the same platform to underpin the Lamborghini Gallardo and Audi's R8, while the Bentley Continental Flying Spur and GT models share components with the VW Phaeton.
BMW, which owns Rolls-Royce, plans to roll out the i3 electric car next year, as it adapts to demand for cleaner cars.
The bulk of Aston Martin's lineup consists of two-door coupes like the DB9, Vanquish and Vantage. It also offers the Cygnet city car, which is based on Toyota's iQ.
The British carmaker's adjusted earnings before interest taxes, depreciation and amortization last year fell 18 percent to 76.2 million pounds, with deliveries steady at about 4,200 vehicles.
The company's factory in Gaydon, central England, where Aston Martin makes most of its cars, is adjacent to an engineering facility for Tata Motors' Jaguar Land Rover.