The euro has fallen to an 11-month low versus the US dollar and global equities are extending losses on Wall St.

Equities on both sides of the Atlantic dropped overnight on disappointment the European Central Bank won't be boosting its bond purchases to help ease the euro zone's fiscal crisis.

Stocks were mixed overnight as investors weighed a round of warnings by credit rating agency Standard & Poor's in two days that would boost borrowing costs throughout the euro zone.