If investors are counting on the banks to help take the index over the 6000 line, they may be disappointed.

Analysts are optimistic another OPEC production cut agreement will eventuate but the prospect of surging shale activity in the US has investors wary.

Oil closed at the lowest in more than a month as Libyan output surged, and Saudi Arabia cut prices to Asian customers.

Janet Yellen will have to clear ever higher hurdles if she wants to pare in an "orderly' way the Fed's $US4.5t balance sheet.

The Australian dollar advanced overnight on expectations that the RBA will signal rates are more likely to rise than fall.

The companies have vast networks of complementary products that feed off one another to generate more sales, making it ever harder for competitors to keep up.