NEW YORK (AFP) - US stocks dived Friday after Britain's surprise vote to leave the European Union, joining a global equity rout amid rising uncertainty about the future of Europe.
The Dow Jones Industrial Average slumped 3.4 per cent to 17,399.86.
The 611-point drop was the index's biggest single-day point loss in nearly five years.
The broad-based S&P 500 plunged 3.6 per cent to 2,037.30, while the tech-rich Nasdaq Composite Index sank 4.1 per cent to 4,707.98.
Although the losses were broad-based in the US, sectors that were especially hard-hit included banking, energy, travel and industrials.
The unexpected British decision also reverberated through other financial markets, slamming the British pound and boosting gold.
Economists expect weaker global growth, and especially a slowdown in Europe, and a higher risk of recession in Britain.
Analysts also expect a hit to the US economy, although not as great as in Europe.
"This was really an event that caught most global investors flat-footed," said Jack Ablin, chief investment officer of BMO Private Bank.
"We're going to see more days like today as the collective wisdom may prove wrong in others cases, too."
Among large banks, Citigroup plunged 9.4 per cent and Morgan Stanley 10.2 per cent. Bank of America, JPMorgan Chase and Goldman Sachs all lost 7 per cent or more.
Large US banks have made London their European headquarters and are expected to face costs associated with retooling their operations.
Gold producers were a rare bright spot as investors flocked to the traditional haven of the gold metal, pushing prices sharply higher.
Barrick Gold jumped 5.8 per cent, Newmont Mining 5.1 per cent and Goldcorp 4.4 per cent.
Travel, airline and hotel stocks sank, with American Airlines plummeting 10.8 per cent, Priceline 11.4 per cent and Marriott International 7.3 per cent.
Analysts worry that travel could be curtailed due to the political and economic uncertainty surrounding Britain and the EU.
Technology shares suffered, with especially ugly falls for Cisco Systems, down 5 per cent; eBay, 6.9 per cent; and NXP Semiconductors, 8.3 per cent.
Apple fell 2.8 per cent and Microsoft 4 per cent. Petroleum-linked shares tumbled on lower oil prices, with Halliburton losing 4.2 per cent, ConocoPhillips 5.4 per cent and Apache 5.7 per cent.