Shares of Tesla Inc. /zigman2/quotes/203558040/composite TSLA +3.62% slumped 5.6% in premarket trading Friday, adding to what is already on track to be the worst weekly performance since the electric vehicle company went public in June 2010. The stock has tumbled 24.6% over the past four sessions; the previous biggest weekly percentage decline was 15.3% during the week ended Jan. 13, 2012. The stock would have to rally 12.4% to close at or above $763.06 not to break the weekly loss record. The selloff comes amid a broader stock market plunge, in which the S&P 500 has lost 10.8% the past 4 days, amid growing fear over the potential negative impact of the coronavirus outbreak. But despite the weekly loss, the stock has still more than doubled (up 105.0%) over the pat three months through Thursday, while the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.48% has lost 5.6%.