After a slight rebound earlier this week, Tesla's TSLA stock is back to falling, keeping with its recent performance. Even U.S. President Donald Trump's purchase of one hasn’t done much to spark real momentum for the electric vehicle (EV) leader.

This suggests that a reaction from consumers who dislike Mr Musk’s antics are only one reason for falling sales. An updated Model Y, Tesla’s best-selling vehicle, has just gone on sale. In preparation Tesla ran down inventory of the old model, crimping supply. Customers doubtless held off purchases until the new car was available.