US debt gloom looms as Aust shares break winning streak

The gloomy start to the week came after ratings agency Moody's downgraded its sovereign credit rating for the United States, and as local investors de-risked ahead of tomorrow's RBA monetary policy announcement.

Nine of 11 local sectors finished in the red, with only telecommunications services and utilities eking out minor gains.

The Australian dollar is buying 63.99 US cents, down from 64.27 on Friday at 5pm.