Jack Dorsey, the cofounder and public face of Twitter, will step down from his role as CEO, effective immediately, the company announced Monday. Dorsey will remain a member of Twitter’s board until at least next year. Parag Agrawal, Twitter’s chief technology officer, will take over as CEO. “I’ve decided to leave Twitter because I believe the company is ready to move on from its founders,” Dorsey said in a statement Monday. “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.” In an internal note, shared on his Twitter account, Dorsey said: “I want you all to know that this was my decision and I own it. It was a tough one for me, of course. I love this service and company … and all of you so much. I’m really sad … yet really happy. There aren’t many companies that get to this level. And there aren’t many founders that choose their company over their own ego. I know we’ll prove this was the right move.” The departure comes six years after Dorsey returned to the chief executive role to help turn around the social network’s business. During Dorsey’s tenure, Twitter achieved profitability, posted its first billion-dollar quarter and began testing and releasing a wide range of features to draw in users. But Twitter, like its peers, has also had to confront the challenge of content moderation as well as growing scrutiny from lawmakers and the public. CNBC was first to report Dorsey’s expected departure Monday. Shares of Twitter jumped as much as 10% in pre-market trading Monday after the report, before giving up some of those gains. While much smaller than rivals like Facebook, Twitter has been central to the debates over whether and how much social media platforms should be responsible for curbing hate speech, violent rhetoric and misinformation on their sites. Dorsey has testified several times before Congress amid criticisms of his company’s handling of user content. At the start of this year Twitter took the extraordinary step of permanently banning a sitting US president from the service following the insurrection at the US Capitol. But under Dorsey’s leadership, Twitter has struggled to design and enforce an ever more complex set of policies and rules for its users, including world leaders. Dorsey has had to navigate those challenges while dividing his time at Twitter with serving as CEO of Square, the payments company he also cofounded. This summer, Dorsey suggested he might be willing to leave Twitter and Square to go work on bitcoin-related initiatives. As recently as last year, Dorsey faced an investor challenge from activist hedge fund Elliott Management pushing for changes, including possibly replacing him. Dorsey ultimately survived. The reports about Dorsey’s looming departure come 15 years after he helped launch the short-messaging company. Dorsey marked the moment with the platform’s first-ever tweet: “just setting up my twttr.” Dorsey first became CEO of Twitter in 2007, but was forced out of the role the following year. He returned as CEO in 2015.