Why it matters: Twitter co-founder Jack Dorsey has stepped down from his role as chief executive officer. CNBC was first to report the rumor, which was just confirmed in an press release from Twitter. Share value in the social networking platform popped on the news before trading was halted.

Dorsey, along with a host of others including Noah Glass, Biz Stone and Evan Williams, launched Twitter in mid-2006. He was the company's original CEO but transitioned to board chairman a couple of years later. He was again named CEO in late 2015 after Dick Costolo left following a six-year run.

Twitter's board has unanimously appointed CTO Parag Agrawal as Dorsey's replacement and a member of the board, effective immediately. Dorsey will remain on the board until his term expires in 2022.

Dorsey said he decided to leave Twitter because he believes the company is ready to move on from its founders. "My trust in Parag as Twitter's CEO is deep. His work over the past 10 years has been transformational. I'm deeply grateful for his skill, heart, and soul. It's his time to lead," said Dorsey.

Some have questioned the executive's abilities to lead two major companies as CEO simultaneously. Just last year, Twitter stakeholder Elliott Management attempted to have Dorsey removed as CEO. Eventually, the investment firm reached an agreement with Twitter's management and relented.

Twitter's stock is currently trading at $48.67 on the news, not too far off its year-to-date- low of around $45. Share value in Square, meanwhile, is down 0.54 percent on the day.

Image credit Anushree Fadnavis