I'd keep a close eye on the Russell 2000 Index to see whether it continues its recent downward plunge below its (now-broken) support and influences the other three Major Indices to follow suit.
The following Year-to-date comparison chart of percentage gains/losses shows that the RUT has lost the most recently (because of its prior double-top spike to 11%), but that all four Major Indices are roughly even in percentage gains now for the year...we'll see if that was just a dead cat bounce and whether the SPX:VIX ratio does plunge below the 100 level, as I mentioned here.