The bottom line: The selling might not be over. Nevertheless, I think it is more of a time to buy than to sell. On average, after a weak October, the October-May gains average 5.3%, well above the average 1.7% gain from May-October since October 1928, says Ed Yardeni of Yardeni Research.
The article is right. However, a fall like this scares weak investors to sell which accelerates the fall and so on. And the bull market has gone on and on for 5 years, pushed by the three QEs that are now over; valuations are high and the upcoming increase in rates will inevitably drive money to bonds.
So I guess the market will go sideways/down for a few years now. No need to panic, it won’t be the end of the world as fundamentals are solid, but there will not be a 5-year-rally like this anytime soon either. And volatility, which shoot up already, will stay up for a while. Which is just perfect for systematic trading.