"As a traditional investor, it doesn't fit any valuation system that makes any sense compared to any other stock," Ross Gerber said of Tesla.

Self-described “long-term optimist” Elon Musk made another bold prediction about his car company. That isn’t necessarily good news for Tesla’s stock price. On Saturday, Musk tweeted that Tesla’s earnings could grow tenfold over the coming five years if its business execution is “outstanding.

Tesla’s stock has dropped by nearly half in three months. Even so, investors are still debating whether Elon Musk's electric-vehicle maker remains overpriced.