http://dealbook.nytimes.com/2012/10/28/nyse-plans-to-close-its-trading-floor/?ref=business

12:50 a.m. | Updated

All United States stock and options markets will close on Monday as Hurricane Sandy approaches, as Wall Street braces for the storm to barrel through the heart of the country’s financial center.

The decision, made on Sunday night, leaves the American stock markets closed for weather conditions for the first time in nearly three decades. The New York Stock Exchange had previously planned on closing only its physical trading floor, while allowing for trading on its Arca electronic exchange. It has now decided to halt all trading.

The Nasdaq and BATS stock markets, which are built on electronic trading, also decided to close. The CME Group, which operates the Nymex commodities exchange, said it would halt trading on its physical commodities floor and on its electronic stock futures and options exchanges.