Tesla confronts an expanded U.S. investigation into its self-driving technology, specifically focusing on how vehicles perform in adverse weather conditions. Federal regulators have escalated their scrutiny as questions mount about the reliability of autonomous systems during rain, snow, and fog. The expanded probe represents a significant challenge for the electric vehicle maker's ambitious autonomous driving ambitions.

The escalation by federal safety regulators could result in a recall campaign or other enforcement action against Tesla. This development underscores growing concerns about the safety of semi-autonomous systems, particularly when environmental conditions deteriorate. Tesla's stock price has historically reacted negatively to regulatory scrutiny of its driver-assistance features.

For investors, the expanded probe introduces uncertainty around Tesla's timeline for full self-driving deployment and potential revenue from the feature. The investigation may prompt competitors to emphasize their own safety protocols in marketing materials. Tesla's valuation has long been tied to its autonomous driving claims, making regulatory challenges particularly concerning for shareholders betting on the technology's future.