Tesla's (NASDAQ: TSLA) highly publicized robotaxi event failed to impress investors, who sent its shares tumbling following the presentation. The stock had rallied over the past quarter in anticipation of the event,

Tesla stock vacillated Monday as investors continued to digest what they learned from the company’s Robotaxi Day held Thursday evening.Shares of the electric-vehicle maker opened $220.13, up 1.1%, then slipped to trade as low as $213.

Tesla shares' 8.8% decline Friday took away $67 billion in market capitalization from the elecric-car maker, the biggest one-day vanishing of value for the stock since July 24, according to Dow Jones Market Data.