Tesla Inc. closed the worst year in the stock’s history, having lost more than $700 billion in market valuation amid investor concerns about production disruptions, demand worries and Chief Executive Elon Musk‘s focus on Twitter Inc.

The electric-vehicle maker’s shares fell roughly 65% from the start of the year. A new wave of share sales unfolded in recent weeks after discounts Tesla offered for people to take vehicle deliveries before year-end spurred fears over demand. The company also has had to deal with its China car plant, its largest by volume, temporarily shutting down. Tesla’s stock in December also suffered its worst monthly performance, though shares closed Friday up 1.12% at $123.18.