Jack Dorsey, the company’s co-founder and chairman, will serve as interim chief executive while the board searches for a permanent successor.
The change is effective July 1. Twitter shares were up more than 7 percent in after-hours trading immediately after the news was announced.
Since Twitter’s debut as a public company in 2013, Mr. Costolo has repeatedly disappointed Wall Street as the company struggled to attract new users, refine its products and develop new forms of advertising.
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