Concerns about China’s economy intensified, accelerating the selloff across global markets as investors tried to assess whether the rout was just a short-term pullback or a signal of deeper trouble.

The market misery marched from China through Europe to the US, where the Dow Jones Industrial Average fell 1,089 points Monday morning - the worst intraday drop in its history - then popped back up like a cork and fell again in a jagged line to finish 588.40 points down, extending a slide that has left the blue-chip index off 11% this year.