Tesla's stock is having a monster month, despite some recent hiccups, including a flawed rollout of its driver assistance software and confusion over whether Hertz really inked a deal with the electric automaker to purchase 100,000 vehicles.

Shares of Tesla are up more than 50% since the beginning of October, and the company's market cap has grown to more than $1.2 trillion. It only passed Toyota, now the second-largest automaker in terms of market cap, last year, but is now nearly $900 billion more valuable.