By Greg Peel

The Dow closed down 22 points, or 0.2%, while the S&P fell 0.4% to 1626 and the Nasdaq lost 0.1%.

Some say it was rumour the Fed was thinking about how to pare back QE, but that story gained little traction and is completely at odds with the Fed's last policy statement. Others say it was something to do with a derivative play in Japanese government bonds, which caused the yen to finally crash through the 100 yen to the dollar mark after having failed so many times. Others say it was simply technical, and no doubt stops were triggered to help the dollar-yen to the 100.68 mark on last count.

Whatever the cause, the US dollar index is up 0.9% in 24 hours to 82.66 as not just the yen, but the euro, pound and Aussie all took a subsequent dive.