Over the past couple months, the US has made consistent new highs over and over. In the past investors have been in pure denial about the possibility of these Indices collapsing (1929) but we're now more knowledgeable to actually understand that bull markets never last forever. This retracment is healthy for the market in my humble opinion, the economy on the other hand may experience slight discomfort (if this correction isn't as big as I think it will be). Since 2014, more than 75 percent of the stock shares traded on United States exchanges (including the New York Stock Exchange and NASDAQ) originate from automated trading system orders. This means that the system will not hesitate to execute a command if it recognizes a pattern. Im sure that number has increased over the years.
This is simply a personal observation. Although it is something I've been watching closely.
The TA above demonstrates H&S patterns that have broken necklines - 38.2 Retracment levels are anticipated.