Stock market volatility deepens as Wall Street faces rollercoaster opening

Wall Street stocks have lurched back and forth in a roller-coaster session for global financial markets (Richard Drew/AP) -

Wall Street stocks have lurched back and forth in a roller-coaster session for global financial markets, as volatility deepened while traders are on edge over how US tariff plans will develop.

The US’s S&P 500 had major swings on Monday.