At 11.32am (EDT) on 8 July, the New York Stock Exchange (NYSE) computers went down, causing a four-hour suspension of transactions. In a four-hour period the NYSE averages about $400m (£259m) in trades – a substantial daily loss.
The NYSE and Homeland Security both quickly announced the problem was not due to a cyberattack.
At around the same time that the NYSE went down, the Wall Street Journal’s website went offline, as did that of popular financial blog Zero Hedge. United Airlines also experienced a “network connectivity issue” which impacted almost 5,000 flights worldwide.
Given the criticality of technology to United Airlines, let’s assume for a moment it has a daily reliability rate of 99.9%, meaning it has a system failure once every 1,000 days – which equates to once every three years. Now, let’s assume the NYSE and the Wall Street Journal also have a daily reliability rate of 99.9%.
If these events were truly random and independent, then the frequency of all three of these events happening on the same day is once in a billion days (or if you prefer to count in years, almost 2.8 million years).