It all started nearly 9 years ago to the day, when in April 2009 we wrote, "The Incredibly Shrinking Market Liquidity, Or The Upcoming Black Swan Of Black Swans", in which we explained how as a result of the growing influence of HFT, quants and central banks, the market itself was breaking.

We also highlighted what the culmination of the market's "breakage" could look like:

liquidity disruptions could and will lead to unexpected market aberrations, such as exorbitant bid/ask margins, inability to unwind large block positions, and last but not least, explosive volatility: in essence a recreation of the market conditions approximating the days of August 2007, and the days post the Lehman collapse...

We even laid out some likely catalysts for a possible market crash: "continued deleveraging in quant funds, significant pre-market volatility swings as quants rebalance their end of day positions, increasing program trading on decreasing relative overall trading volumes."