US stocks slumped on Tuesday after China upped the ante in its trade spat with the US, rattling investors' nerves as big Wall Street's banks kicked off earnings season. The Dow Jones Industrial Average (^DJI) slid 0.9%, while the S&P 500 (^GSPC) dropped 1%. The tech-heavy Nasdaq Composite (^IXIC) sank over 1.4% to lead the retreat. The mood has soured after stocks' strong rebound on Monday thanks to a fresh round of retaliation from Beijing to President Trump's trade salvos. Its latest moves to target U ...