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.

The kiwi dollar dipped below 78 US cents as markets digest the coordinated moves by the world's biggest central banks to cut borrowing costs.

World share markets are down, with worries about Europe overwhelming good economic data from the US.

New Zealand's terms of trade - the amount of imports that can be funded by a fixed quantity of exports - fell in the third quarter, driven by falling prices for primary sector exports and a strong kiwi dollar.