In a nut shell this is a normal correction in a big booming bull market. Statistically, on average the market has around three 5% corrections in a year. Therefore this is normal market volatility. The fundamentals of the economy & the market have not changed:
Unfortunately these corrections don’t last that long, therefore investors with cash on the sidelines need to take advantage of this short term dip in prices before it is too late. When the US markets sold off earlier this year, it then went onto to hit new highs.