Elon Musk, Tesla boss, runs to a Tesla at the Tesla Gigafactory construction site. In Grünheide near Berlin, a maximum of 500,000 vehicles per year are to roll off the assembly line starting in July 2021. Julian Stahle | picture alliance | Getty Images (This story is for CNBC PRO subscribers only.) Tesla is joining the S&P 500, and with the stock currently trading at all-time highs, Miller Tabak's chief market strategist Matt Maley broke down the key technical levels for investors to watch going forward.