Tesla Inc dropped 14% in a single day yesterday, representing one of its most significant one-day falls in the past few years.

Another concern has investors selling Tesla stock today. Musk has started very publicly splitting with President Trump and other Republicans over the spending bill making its way through Congress. That could have ramifications as Musk lobbies regulators for a federal approach to autonomous driving rules.

Tesla Motors' stock price is taking a beating again, this time because of the very high-profile squabble between chief executive Elon Musk and US President Donald Trump. Its 15 per cent decline on Thursday reflects the volatility that shadows the company's shares,