The two car companies forged a technical partnership last summer that resulted in Daimler owning five per cent of non-voting shares in Aston Martin.
Speaking at the Paris motor show, Zetsche said the current five per cent stake Mercedes has in Aston is ideal because it “would not be in Aston’s interests to be incorporated into a big corporate organisation, as it would include risk”.
He added: “Aston is only 4000 units a year so there is also a danger we would be distracted from our core business. The deal is a perfect fit for both brands as it allows Aston to remain independent but also benefit from outside technology.
“There are no plans to increase our stake or take over.”
Zetsche also welcomed the arrival of Andy Palmer from Nissan to head Aston. “I regret Andy Palmer leaving Nissan as he was very positive to work with for us, but as he’s left I welcome him to Aston and look forward to future co-operation.”
Zetsche also revealed that the imminent return of the Maybach was likely to see the badge used in a similar way to Mercedes-AMG, meaning super-luxury versions of the S-class could become Mercedes-Maybach models.
“I don’t see a range like Mini for Smart,” he said. “Smart is not an SUV brand.”
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