Twitter (NYSE:TWTR) co-founder Jack Dorsey has announced that he is stepping down as chief executive officer (CEO) of the social media company.

Dorsey will be replaced at the helm of Twitter by the company’s current Chief Technical Officer Parag Agrawal.

Dorsey co-founded Twitter in 2006 after coming up with the concept for the social media platform while an undergraduate student at New York University, and has been serving as CEO of both Twitter and digital payment firm Square (NYSE:SQ), which he also co-founded.

Dorsey said he has “deep trust” in his replacement. Agrawal joined Twitter in 2011 and has been the firm’s head of technology since 2017.

Dorsey challenged corporate conventions with his nose ring, long beard, and a wellness regime that includes yoga and eating only one meal a day. But he came under pressure from investors, who felt Twitter was not getting the focus it needed while Dorsey was also running Square.

Twitter’s share price jumped as rumours of Dorsey’s departure emerged, but by mid-afternoon Monday (November 29) shares were trading just under their value at the end of last week.

In many ways, Dorsey typifies the Silicon Valley chief executive. He’s a multi-billionaire who dresses in tie-dye t-shirts and has high ideals for how technology can change the world.

Dorsey is also a notorious cryptocurrency bull and has said that Bitcoin has the ability to create “world peace.”

In addition to his CEO role, Dorsey is also giving up his board seat at Twitter. That’s different from Jeff Bezos, who retains influence at Amazon despite stepping down as the CEO of that company earlier this year.