Falling exports have hurt US economic growth
The US economy shrank at an annual rate of 6.2% in the last three months of 2008 official figures show, a far sharper fall than previously reported.
Plunging exports and the biggest fall in consumer spending in 28 years dragged the annualised figure down from an earlier estimate of 3.8%.
The decline was much worse than analysts had expected, sending US stocks spiralling lower.
In 2008 as a whole, the economy grew by 1.1%, the slowest pace since 2001.
The blue-chip Dow Jones industrial average dropped 119.15 points, or 1.66%, to 7,062.93. The broader Standard & Poor's 500 Index fell 2.36% to 735.09 - a 12-year low.
Consumer spending, which accounts for about two-thirds of domestic economic activity, fell by a rate of 4.3% in the final quarter - the biggest fall since the second quarter of 1980. This was a revision of the earlier figure of 3.5%.
With rising unemployment, sliding home values, increasing numbers of repossessions and the slumping value of investments, observers say many US consumers are hanging on to whatever disposable cash they have.
Meanwhile, exports - which had until recently been supporting the economy - fell at the sharpest rate since 1970 at an annual rate of 23.6%, down from 19.7%.
Earlier this week, Federal Reserve chief Ben Bernanke warned Congress that without the right policies from the government, the US recession could last into 2010.
But he said if the Obama administration and the central bank can restore some measure of financial stability, 2010 could be a year of recovery.
President Obama recently signed a $787bn (£556m) recovery package of increased government spending and tax cuts, and unveiled a $75bn scheme to stem repossessions.
No good news
The latest GDP figures were "just awful" said Matt Esteve, a currency trader at Tempus Consulting in Washington DC. "It shows the weak state of the world's largest economy."
And Boris Schlossberg, director of currency research at GFT Forex said there was "doom all over".
He predicted that the dollar would not weaken too much against the euro because "there's no good news on the other side of the Atlantic, either".