NYSE president Stacey Cunningham: September is on track to be the busiest month for IPOs due to pent-up demand

Many companies are going public in September coming after an IPO pop in August. Shares of Unity, a video game software developer, jumped more than 34% in its market debut Friday on the New York Stock Exchange. Stacey Cunningham, New York Stock Exchange president, joins 'Closing Bell' to discuss.