VW’s preferred stock fell as much as 7% in early trading in Frankfurt, but recovered by mid-afternoon to be down only 4.7% on the day. The shares had been risen some 40% from the lows they hit after the scandal broke in September, mainly thanks to German regulators accepting a low-cost fix for the biggest of its emissions-related problems in its home European market. As of today, the company is worth $15 billion less than before the scandal broke.

The Department of Justice filed its first civil suit against Germany’s largest automaker Monday for violating environmental laws by installing so-called ‘defeat devices’ that enabled cars to run with deceptively low emissions of harmful nitrogen oxides during testing. Actual emissions in real-world conditions were many times the legal limit.

VW is now facing up to $37,500 in penalties on each of four counts of violating the Clean Air Act, for every one of the nearly 600,000 affected cars it sold in the U.S. since 2009. That means a maximum theoretical liability of nearly $90 billion, well above initial estimates of $18 billion and more than the company is worth right now. The DoJ’s stance appears to have hardened after the company failed to admit that it had failed to come clean about defeat devices installed in some of its 3-liter engines, even after the Environmental Protection Agency had made its first allegations in regard of smaller vehicles.

Moreover, that $90 billion only covers civil claims under the Clean Air Act, and doesn’t preclude a criminal case which could extract stiffer penalties (albeit requiring a much higher level of proof). It also doesn’t include the class actions against the company from investors, dealers and owners.

“People are always afraid when they see these huge numbers popping up, but history suggests the final cost won’t be as severe as these potential fines appear,” said Arndt Ellinghorst, head of global automotive research at Evercore ISI in London. Ellinghorst says the final cost is still impossible to forecast accurately due to the unpredictability of the litigation process.

Bloomberg reported Tuesday that chief executive Matthias Müller will visit the U.S. next week to meet “politicians and possibly other officials” next week for the first time since the crisis broke, in an effort to mollify U.S. authorities. Similarly, VW brand manager Herbert Diess will make his first appearances in months in the U.S., at the Las Vegas Consumer Electronics Show and the Detroit Motor Show next week.

No-one at VW could be reached to confirm details of Müller’s trip.

Volkswagen said it will “continue to work cooperatively with the EPA on developing remedies.”