Tesla shares fell by 4% Monday morning, shaving nearly $5 billion off of the fortune of CEO Elon Musk as of 10:30 a.m. ET. That was enough to knock Musk back to the number two spot on Forbes’ list of the world’s richest people, trailing Bernard Arnault of French luxury conglomerate LVMH, worth $186 billion. Musk was worth $184 billion.