New York:Wall Street delivered its worst-ever post-election session Wednesday as major stock indices lost more than five percent, one day after the US market's biggest-ever election day gains.

Tuesday trading saw gains of more than three percent on Wall Street, even as voters were choosing Democrat Barack Obama over Republican John McCain for a four-year presidential term starting in January.

On Wednesday, though, economic reality set in with a private report showing a rapidly rising job losses. Another report on the labour-intensive service industries found a sharp contraction.

The blue-chip Dow Jones Industrial Average lost 486.01 points, or 5.05 percent, to 9,139.27. The broader Standard & Poor's 500 Index was down 52.98 points, or 5.27 percent, to 952.77. The technology-heavy Nasdaq Composite Index fell 98.48 points, or 5.53 percent, to 1,681.64.

The dollar rose against the Japanese currency to 99.699 yen from 99.244 yen Monday. The dollar dipped against the euro to 76.863 euro cents from 79.233 euro cents Monday.