On July 8, 2015, trading on the New York Stock Exchange (NYSE) was temporarily halted for a few hours as the result of “an internal technical issue” that was “not the result of a cyber breach.”

While such a suspension of trading has not happened to the NYSE before, small technical glitches have resulted in major outages including Google blocking the entire internet with a data entry mistake, NASA crashing a Mars Orbiter because they failed to convert to the metric system, and the Navy leaving the USS Yorktown dead in the water when they divided by zero.

Software glitches happen, as do security breaches, but they are not the end of the world.

The NYSE is one of the largest exchanges in the United States, but it is by no means the only stock exchange. Trades were simply rerouted to one of the other exchanges (NASDAQ or NYSE ARCA), both of which normally have higher trading volumes. Under normal conditions, the NYSE has just under 10% of the trading volume, although they are higher than that in capitalization.

The ability to trade equities on multiple exchanges, both in this country as well as around the world, offers both liquidity and redundancy. It protects against both glitches and attacks alike. Foreign stocks are traded on the US markets and major US stocks are traded on a host of foreign markets. The major world markets include: the Tokyo Stock Exchange, the NYSE Euronext, the London Stock Exchange, the Shanghai Stock Exchange, the Hong Kong Exchanges, the Toronto Stock Exchange, the Bombay Stock Exchange, the Bovespa in Brazil, the Australian Stock Exchange, the Deutsche Borse in Germany, the Spanish Exchanges, the National Stock Exchange in India, and the Swiss Exchange.

The suspension of trading on the NYSE doesn’t fit in a special category of alarm, nor does it require action on the part of shrewd investors.

So, what should you do? What you always do: rebalance your portfolio. If not today, then tomorrow.

Photo used under Flickr Creative Commons.