New York City’s financial authorities have decided to close the markets today as Hurricane Sandy moves in. It’s the first time since 1985 that a weather event has shut down trading.

Initially officials were only planning to shut down the physical trading floor, but opted for a total shut down of trading — in person and electronic — citing employee safety and market integrity. Market officials and regulators were concerned about how well trading could function if systems were disrupted by power outages.

Globally, the shut down in New York is not expected to make much of an impact. Jan Randolph at IHS Global Insight in London says, “There are other markets in the world besides New York — there’s London, Europe and Japan and Asia — so it’s not as if the entire financial system shuts down. It’s equivalent to a one or two day holiday.”