When trading opened on Nyse on Tuesday morning, shares in more than 250 companies went haywire, with some seeing price swings of more than 25 percentage points. The issue forced Nyse to cancel thousands of trades.

The exchange initially blamed a "technical issue" for the swings, which sent investors panicking.

According to Bloomberg, the cause was human error from a Nyse staffer at its backup data centre in Chicago.

On Monday, the employee did not shut down a disaster recovery system overnight. This led the exchange’s system to treat the Tuesday opening bell as a continuation of trading, missing the opening auctions that set initial prices.

This led to orders at strange prices, tripping the Nyse circuit breakers, which are designed to stop wild price swings.