The AUD/USD currency pair, which expresses the value of the Australian dollar in terms of the U.S. dollar, tends to correlate with global market risk sentiment. This positive correlation has held up recently, as shown in the chart below, with AUD/USD falling alongside the drop in U.S. equities (as measured by the S&P 500 equity index).
(Chart created by the author using TradingView. The same applies to all subsequent candlestick charts presented hereafter.)
In the chart above, the daily candlesticks illustrate AUD/USD price action, while the blue line represents the S&P 500