Tesla Had A Roller Coaster Week

Tesla started the week with a slide below $240 per share. But then CEO Elon Musk tweeted about something called the "D" being unveiled Oct. 9 and the stock rallied.

It closed on Friday at $255, up around 8% from the trading lows visited during the week.

Shares are still off from a trading day peak of $291, reached on Sept. 4.