On Thursday, oil prices crashed. And on Friday, shares of oil companies around the world followed suit. Here were some of the biggest losers on Friday: BP (BP), down 5% Royal Dutch Shell (RDS.A), down 6% Total (TOT), down 5% Statoil (STO), down 14% Exxon Mobil (XOM), down 5% ConocoPhillips (COP), down 9% Marathon Oil (MRO), down 13% Occidental Petroleum (OXY), down 7%