STORY: Tesla shares had the worst day in eight months on Tuesday (December 27) as the electric carmaker's stock fell 11.4%.
It comes after a Reuters report said Tesla planned to run a reduced production schedule in January at its Shanghai plant.
That worried investors about a drop in demand in China, the world's biggest car market.
Tesla's stock was the biggest drag on the benchmark S&P 500 and the tech-heavy Nasdaq index on the day.
It has lost more than half its value since the start of October.
As investors worried CEO Elon Musk had become distracted by his takeover of Twitter.
Tesla's production cuts in Shanghai come with a rising number of health crisis infections in China.
Reuters analysis also showed Tuesday that prices of used Tesla cars were falling faster than those of other carmakers.
That had also weighed on demand for new vehicles rolling off the assembly line.