Global markets weakened slightly overnight, although trading was fairly choppy given the lack of economic catalysts.

The Dow Jones broke through 16000 for a second time, but couldn't build on its gains, as traders looked to take profits after the blue chip index's recent run higher.

Sentiment was not helped by disappointing earnings from retailer Best Buy, whilst other investors were content to remain on the sidelines ahead of a speech by Ben Bernanke later this morning.

The Dow slipped nine points (-0.1%) to 15967, the Nasdaq dropped 17 points (-0.4%) to 3932 and the S&P500 let go of four points (-0.2%) to 1788.

In commodity markets, oil edged up 0.4% to US$93.36 a barrel.

Traders were cautious ahead of a crucial meeting between Iran and the West over its nuclear program, which may see trade sanctions against the rogue nation eased.

The US dollar was mostly weaker against other currencies, as traders look to Bernanke's speech today for clues on when the Fed will begin tapering stimulus.

In economic news, the Melbourne Institute Leading Index is due for release at 10:30am, AEDT.

Morning Market Update: Soft Start Ahead is a post from: Australian Stock Report Market Pulse Blog