https://arstechnica.com/tech-policy/2019/09/trump-admin-threatens-california-automakers-over-emissions-deal/

Four major automakers that recently reached an agreement with the state of California to hold to certain emissions standards over the next decade are now the target of a federal antitrust investigation.

Ford, Honda, BMW, and Volkswagen confirmed to media they have been contacted about the probe, which was first reported by The Wall Street Journal.