SAN FRANCISCO, Oct. 5 (UPI) -- Twitter founder Jack Dorsey was named the social media company's official CEO on Monday after serving in the role temporarily since July.
Twitter announced the move in a filing with the Securities and Exchange Commission. It said Dorsey would leave his current post as chairman, which he has served in since October 2008. In addition to serving as Twitter's CEO, Dorsey will remain chief executive of his startup Square, Inc. which he founded in 2009.
Dorsey was appointed to interim CEO following the resignation of Dick Costolo in July. Costolo quit amid several executive changes, misguided product strategy and growing pressure from investors who said Twitter was yielding disappointing user growth.
Dorsey previously served in the role of CEO at Twitter until 2008 when he was replaced by Evan Williams.
Since going public in November 2013, Twitter has reported a loss each quarter and its overall size still lags behind that of Facebook. The site has an average 316 million monthly users.
Twitter shares have also decreased by nearly half their value in the past year; they closed Friday at $26.31 a share. On Monday, though, Twitter shares rose by 1.3 percent to $26.65.
Costolo also resigned from Twitter's board Monday, leaving co-founder and former CEO Evan Williams as the only former CEO to be on the board.
Dorsey's agenda during his time as interim CEO concentrated on faster product improvement, such as the option of having a "buy" button on tweets by major retailers like Best Buy.
Additionally, Dorsey and other exectives' Project Lightning is still in the works.The service is a new video offering that will also allow top tweets to be shown by subject.
Twitter also said Monday that it chose Adam Bain, 42, as its chief operating officer. Bain was previously Twitter's head of revenue and partnerships since September 2010.