Wall Street stocks tumbled on Thursday as most large tech shares continued a retreat while a closely watched risk index pushed higher.

Tech shares have been under pressure in recent days amid talk that the market is "overbought" after a torrid run so far in 2024 on bullishness over artificial intelligence.

The "VIX" volatility index rose about 10 percent in a move that some market watchers tied to political pressure building on President Joe Biden to exit the 2024 campaign.

The Dow Jones dropped 1.3 percent to 40,665, retreating after three straight records.

The S&P 500 dropped 0.8 percent to 5,544, while the Nasdaq declined 0.7 percent to 17,871.

The losses were broad-based, with energy the only one of 11 industrial sectors to advance in the S&P 500.

Art Hogan, chief market strategist at B Riley Wealth, noted that Thursday's losses were broad-based and included smaller equities that had benefited in recent days from the tech selloff.

"It doesn't take much of an excuse for markets to take some profits when they've had such a good run," Hogan said.

Regarding politics, Hogan said, "the market doesn't like uncertainty."

Spartan Capital's Peter Cardillo said speculation about Biden "could create some short-term election anxiety" after more investors expected a win by Donald Trump following their June presidential debate.

The European Central Bank meanwhile held borrowing costs steady, giving policymakers more time to assess progress on inflation after last month's first interest rate cut in five years.

United Airlines shed 1.2 percent after reporting higher profits in the second quarter but cautioning that it would trim back capacity later in 2024 due to excess flights in the US market.

DR Horton jumped 10 percent after reporting higher profits and revenues.

"Although inflation and mortgage interest rates remain elevated, the supply of both new and existing homes at affordable price points is still limited, and demographics supporting housing demand continue to be favourable," said David Auld, executive chairman of the homebuilder. (AFP)