Mayor Michael Bloomberg has rung Wall Street back to business. Traffic is snarled, subways out of commission, streets flooded and power out for many parts of the city, but the New York Stock Exchange opened without hitch Wednesday after an historic two-day shutdown, courtesy of Hurricane Sandy. Mr. Bloomberg rang the opening bell at 9:30 a.m., right on schedule, as stock traders cheered from the iconic trading floor below, rumored to be flooded, but dry Wednesday morning, and festive. The market got off to a good start after the shutdown. The Dow Jones industrial average rose 74 points to 13,182 shortly after the opening bell. The exchange is running on backup generators since power is nonexistent in large parts of downtown Manhattan. The last time the exchange was closed for two days due to weather was in 1888. The Standard & Poor's 500 index rose nearly six points to 1,418. The Nasdaq composite slipped less than one point to 2,987. The government releases its October employment report on Friday. Global markets remained relatively buoyant while U.S. financial markets were shut, and they rose again Wednesday on strong earnings from automakers in Europe and the U.S.