Tesla (NasdaqGS: TSLA) shares plunged Friday, dragging down consumer discretionary sector-related exchange traded funds. On Friday, the Consumer Discretionary Select Sector SPDR (NYSEArca: XLY) fell 3.6%, the Vanguard Consumer Discretionary (NYSEArca: VCR) dropped 3.3%, and the Fidelity MSCI...