Twitter Inc (TWTR.N) CEO Dick Costolo is stepping down, under pressure from investors frustrated by the Internet company's slow growth and seemingly constant shake-ups in its upper ranks.
Costolo will be replaced by co-founder Jack Dorsey on an interim basis.
The company's shares rose 7.7 percent to $38.60 in after-market trading.
In a statement, Costolo said he was "tremendously proud" of his six years at Twitter.
"I am deeply appreciative of the confidence the board, the management team and the employees have placed in me over the years," he said.
Costolo, who will step down on July 1, will continue to serve on the board, the company said in a regulatory filing. (1.usa.gov/1Gwr28k)
Costolo has agreed to cancel all of his remaining unvested equity in Twitter after July 1. Dorsey, who will continue to serve as CEO of Square Inc, had served as Twitter's president and CEO from May 2007 to October 2008.
Twitter has long struggled to gain users at the rate of other social media companies, such as Facebook Inc (FB.O) Instagram and Snapchat.
Data firm eMarketer projects that Twitter's monthly user base will grow at 14.1 percent this year, compared to more than 30 percent two years ago.