Hurricane Sandy aka Frankenstorm caused record flooding in New York City, inundating parts of Lower Manhattan and the financial district.
The Wall Street area was partially flooded as waters surged to a record level of 13.7ft (4.15m) in Lower Manhattan.
New York Stock Exchange is to remain closed on Tuesday.
"We intend to re-open our U.S. markets on Wednesday ... conditions permitting," Financial market operator NYSE Euronext said.
375,000 residents were ordered to evacuate the area as seawater and the Hudson River surged to swamp subways, road tunnels and underground car parks.
"The New York City subway system is 108 years old, but it has never faced a disaster as devastating as what we experienced last night," NYC transport director Joseph Lhota said.
500,000 homes in Manhattan suffered from power cuts.