The U.S. oil price sank into a bear market on Wednesday, falling more than 20% below its April peak, as the global-growth worries gripping financial markets were compounded by fears of a supply glut. U.S. crude futures closed down 3.4% at $51.68 a barrel, dropping below the $53.04 level needed to push oil into another bear market after government data showed a surge in domestic stockpiles. The declines highlight investors’ fears that trade tensions will further undermine economic expansion around the world. …