Nikola stock falls 30% after Executive Chairman Trevor steps down

US electric truck maker Nikola's stock plunged as much as 30% on September 21 after its Founder, Trevor Milton, voluntarily stepped down as the Executive Chairman. Currently, Nikola is trading at $27.58 per share. Shares of General Motors, which earlier announced taking an 11% stake in Nikola worth about $2 billion, lost over 6%.