This week serves as a good reminder to market participants that investing is a marathon and not a sprint – and that the path of the race has always been up and to the right. That said, today's trajectory was straight down,

Futures for the S&P 500 dipped 3.6% before the bell, while futures for the Dow Jones Industrial Average shed 3.4%, dropping below the 40,000 mark. The AP noted that Nasdaq futures tumbled 4%. This comes after Thursday’s collapse, Wall Street’s worst day in five years.