Vanity Fair New Establishment Summit - Day 2

Twitter on Thursday announced that CEO Dick Costolo will step down on July 1. Twitter co-founder Jack Dorsey will serve as interim CEO while the company searches for a permanent replacement for Costolo.

The news follows criticisms from some of Twitter's major investors, including billionaire Chris Sacca, who recently authored a 8,000-word blog post full of recommendations for the company.

"I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the Company," Costolo said on Thursday "We have great leaders who work well together and a clear strategy that informs our objectives and priorities. There is no one better than Jack Dorsey to lead Twitter during this transition. He has a profound understanding of the product and Twitter's mission in the world as well as a great relationship with Twitter's leadership team. I am deeply appreciative of the confidence the Board, the management team and the employees have placed in me over the years, and I look forward to supporting Twitter however I can going forward."

Costolo will remain on Twitter's board and will help the company search for his replacement.