Reports in Germany suggest that Volkswagen, BMW, Audi and Porsche may have secretly conspired on vehicle development including technology for diesel emissions.
German magazine Der Spiegal suggests that around 200 employees sat on 60 industry committee and discussed car specifications such as brakes, petrol and diesel engines,clutches and transmissions along with exhaust treatment systems.
Volkswagen is already mired in a compensation payout amounting to tens of billions of euros after admitting to manipulating diesel emissions in 2015.
The manufacturer says the total cost of the emissions cheating scandal is €18.2bn.
The discovery led to the recall of millions of cars including iconic brands Mercedes-Benz, Audi, Volkswagen and now Daimler.
A spokesperson for Volkswagen, which owns Audi and Porsche, said the group would not comment on ‘speculation and conjecture.’
BMW and Daimler also declined to speak.