The AUDUSD sellers are making a play in the early US trading hours to start the trading week.
The price has now moved below its 100 hour moving average at 0.6432, and also below the 38.2% retracement of the September trading range of 0.64287 (see chart below).
The next key downside hurdle comes in at the 0.6415 level where both the 200 hour moving average (green line in the chart below) and the 50% retracement of the September trading range is found. A move below that level would open the door for further selling toward the 0.6400 area.
It would now take a move back above the 100 hour moving average to frustrate the sellers and lead to a more positive bias in the short term for the AUDUSD. Absent that the sellers are more in control.