An American business journal says profits made by the top 500 United States corporations plunged 85% in 2008.
Fortune magazine says earnings dropped from $US645 billion in 2007 to $US98.9 billion, marking the largest one-year decline in the 55-year history of its Fortune 500 list.
Financial and automotive sectors were the worst affected.
Energy and oil companies hold three of the top four positions in Fortune's latest annual listing of America's biggest companies. They were led by ExxonMobil ahead of Wal-Mart.
Chevron was third followed by ConocoPhilipps and General Electric. General Motors was sixth, despite being on the verge of bankruptcy, followed by Ford in seventh place.
Meanwhile, President Barack Obama says significant risks remain for the US economy despite encouraging signs of stability.
In an interview with Fortune, Mr Obama said further reforms are needed, notably to beef up regulatory powers over the finance industry.
Latest government figures show the US economy contracted by 6.3% in the last quarter of 2008.
A modest return to growth is not expected by economists until the third quarter of this year.
