Conoco split into today different companies. PSX is in the spin off, and that's why the big drop happened. For every 2 shares of COP, shareholders received 1 share of PSX. It was a glorious split, PSX is up 80% after the split, and COP is up about 8%. Win win for everyone involved.
Just wish i shifted more of my COP into PSX after the split. But either way im happy.