I have been short S&P500 for a few months and FTSE100 since summer of last year: the climb up has never been a matter for bullishness, so the August 2015 correction we saw could, in theory, return this month, with the month's historic combination of lull/low activity being less able to cushion shocks and subsequent volatility. Personally, I would be unable to explain why the last 24-48 hours have brought the pullback on equities, but if you saw it with the longer-term view of a due correction or bubble-burst scenario then you would struggle to see how anyone would comfortably take a long position at such levels, with such low VIX readings, with so much uncertainty among increasingly nervous long-only investors...