The intraday moves in FX have led the way
Last week there were a series of bounces and slumps in equities but it was notable that FX moves came ahead of stocks.
At the moment, the S&P 500 is slightly off the highs of the day while FX has fallen more quickly. If the pattern holds, it's a sign of more equity selling to come.
AUD/USD is as good an indicator of this as anything at the moment but note that it's trying to hold intraday support at 0.7309. A break of that could be the tipping point.