Volkswagen has defended its record after allegations that it teamed up with other German car giants to breach EU cartel rules.
VW said it was normal for manufacturers to exchange technical information to speed up innovation.
However, it declined to comment on specific allegations that five German carmakers colluded on price and technology.
Daimler has also called the allegations speculative.
EU and German anti-trust regulators are looking at allegations that BMW, Daimler and VW, including its subsidiaries Audi and Porsche, collaborated for decades on many aspects of development and production, disadvantaging customers and suppliers.
In a statement following an emergency meeting, the VW Group said: "It has no comment to make at the present time on details of these issues or on speculation."
It added: "It is quite common for car manufacturers all over the world to engage in an exchange on technical issues in order to accelerate the pace and quality of innovations."
It said this reduced costs for customers.
VW is already facing tens of billions of pounds in compensation and fines after admitting to cheating on diesel emissions tests.
Despite the scandal, VW's operating profits more than doubled in the second quarter, helped by cost cutting and higher-margin new models.
Underlying profits grew to 4.5bn euros (£4bn) compared with 1.9bn in the same period last year.