Investors must decide whether this is a buying opportunity or a time to sell Tesla stock.

A new design ethos was on full display at the Tesla Robotaxi event, offering some not-so-subtle hints of what to expect from a future sub-$30,000 Tesla.

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.