Stocks fell sharply Thursday, with all three major indexes - the Dow, S&P and Nasdaq, posting their worst day since March 16. Furthermore, the Dow and S&P are on track for worst week in three months. Matt McCall, Founder and President at Penn Financial Group, discusses what contributed to today's massive sell-off. McCall also feels this is a blip during a period where stocks have gradually trended positively over the past couple months.