Another selloff in Tesla Inc.'s stock TSLA, -1.76% on Tuesday, toward a more than two-year low, could drop the electric vehicle maker down to 13th on the list of most valuable S&P 500 SPX, +0.59% companies. The electric vehicle maker's stock slumped 3.3% toward a seventh-straight loss in premarket trading, with recent trading prices implying a market capitalization of about $375.96 billion, down from $388.88 billion as of Friday's close.