From what I notice, February is usually a down month. Same with September and October periods. We are seeing just that in 2018. The recent drop reminds me of what we experienced back in early 2018. The recent volatility is linked to trade war tensions with China, the rising interest rate problem of the Fed, housing slowdown, auto slowdown, and the unexciting guidance from several companies including the industrials which are quite an important gauge on the economy.
The sectors that got hit very hard recently were cyclicals and technology. We saw industrials, materials, discretionary, and technology companies drop in value. At first the consumer staples and utilities were shelter areas for the declines as they were seen as safer areas during slowdowns. However these two sectors also eventually saw declines as the overall averages continued to drop. In today's markets, stocks seem to sell together as a lot of investors today use index funds which lumps everything in one group. Good stocks and bad stocks all got thrown out the window together. This provides a good opportunity to pick the high quality ones.