Stock markets slid across the board on Tuesday as investors worried about lofty tech valuations on the eve of earnings from AI chip titan Nvidia.

Bitcoin also briefly fell below the key $90,000 level for the first time in seven months before rising to $93,000.

With US markets slumping on opening after a rough day of trading in Europe and a sharp sell-off in Asia, Nvidia itself gave up 2 percent mid-session.

"The tech-focused sell-off seen in the US has evidently resulted in global contagion," said Joshua Mahony, chief market analyst at Scope Markets.

Traders increasingly believe the US Federal Reserve will decide against an interest-rate cut next month.

Fawad Razaqzada, market analyst with StoneX, pointed out that usually reliable commodities like gold and copper had also been forced

See Full Page