Dick Costolo resigns as CEO of Twitter in June 2015. Twitter co-founder and chairman Jack Dorsey will be the interim CEO. This follows a high turnover in senior managers at the company, with the departure of the COO, CFO, and replacement of 4 product chiefs. Quick decisions by Costolo in the early days before the IPO helped the company, but are now seen as a weakness for Twitter. Twitter share price was down 20% after reporting weak revenue growth for the last quarter.