Operation Twist - the Federal Reserve's latest attempt to boost economic growth in the US - sent markets globally tumbling overnight, with major indices in the US and Asia shedding up to 3%.
US markets fell 2% at open, adding to the grim picture in Europe, as investors continued to fret over the future of Greece.
The FTSE 100 sold off sharply in early trading alongside indices across Europe as fears over a break-up of the region swept across markets once again.
It has been an uncomfortable summer for investors as the credit crisis from 2008 continues to plague markets, this time in the guise of a sovereign debt crisis. But how have markets really coped?
Capital Economics has lowered its year-end forecast for 10-year US treasury and UK gilt yields in light of a deteriorating growth outlook.
US markets opened lower this afternoon, following falls across Europe today as fears of a Greek default resurfaced once more.
Major European and US indices have dropped as the ECB revealed a key official was stepping down.
UK shares were muted at the open, failing to take advantage of yesterday's 3% rise in the S&P 500.
US markets opened sharply lower on Tuesday, having missed the sell-off at the start of the week, before services data helped improve sentiment.