Tesla shares just took a dive

Tesla made a big announcement on Wednesday night: all its future vehicles will have the capability to fully drive themselves.

That represents a huge leap forward for autonomous vehicles and in particular for Tesla's Autopilot technology.

But investors aren't impressed. In early trading in Thursday, Tesla slipped 3%, to $198, after climbing above $205 on Wednesday during the trading day and closing at $203.

There's two reasons for investors to fret about the self-driving promises. First, the technology will be expensive: $8,000 on new vehicles.

Second, though Tesla has just taken a massive theoretical lead in the race to get a fully autonomous car on the road, the validation process could take years, as the carmaker orchestrates the complex hardware and software.

Google Finance