Jack Dorsey resigned as CEO of Twitter, saying the social network “is ready to move on from its founders,” the company announced Monday.

Dorsey, 45, also serves as CEO of payment company Square — and some investors, including hedge fund Elliott Management, had wanted Dorsey to exit as chief executive of Twitter so the social media company could have a CEO fully focused on Twitter.

Twitter said its board of directors unanimously appointed Parag Agrawal, currently Twitter’s chief technology officer, as CEO and a member of the board, effective immediately. Shares of Twitter initially shot up as much as 11% in the wake of the news, which had been reported earlier by CNBC — but soon fell into negative territory and closed down 2.7% for the day.

“I’ve decided to leave Twitter because I believe the company is ready to move on from its founders,” Dorsey said in a statement. “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.”

SEE ALSO: Who Is Parag Agrawal? A Look at Twitter’s New CEO

Dorsey co-founded Twitter in 2006. He took over as Twitter’s CEO after former chief exec Dick Costolo exited the post in June 2015. In a memo Monday to employees about his resignation, Dorsey said having a company be “founder-led” ultimately is “severely limiting and single point of failure.”

“[T]here aren’t many founders that choose their company over their own ego,” Dorsey wrote, patting himself on the back for stepping down as CEO. “I know we’ll prove this was the right move.”

Also in the memo, he wrote, “I want you all to know 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.” Dorsey posted the memo on Twitter (adding at the bottom: “My one wish is for Twitter Inc to be the most transparent company in the world. Hi mom!”):

Dorsey will remain a member of Twitter’s board until his term expires at the 2022 meeting of stockholders (which will be “May-ish” in 2022, according to Dorsey). Bret Taylor, president and COO of Salesforce, was named Twitter’s new chairman, succeeding former Google CFO Patrick Pichette, who will remain on the board and continue to serve as chair of the audit committee.

Taylor said in a statement, “On behalf of the board, I want to thank Jack for his visionary leadership and unrelenting dedication to Twitter since its founding. Jack returned to Twitter and turned the company around at the most critical time. The progress since then has been nothing short of incredible. Jack has given the world something invaluable and we will continue to carry it forward.”

Last year, Pichette had said Twitter’s board created a special committee that would “provide a fresh look” at Twitter’s executive leadership structures.

Agrawal joined Twitter in 2011 and has served as CTO since October 2017 overseeing technical strategy. Prior to being appointed CTO, he was named Twitter’s first distinguished engineer because of his work across revenue and consumer engineering, including “his impact on the re-acceleration of audience growth in 2016 and 2017,” according to Twitter. Agrawal holds a Ph.D. in computer science from Stanford University and a bachelor’s degree in computer science and engineering from the Indian Institute of Technology, Bombay.

Agrawal also shared his memo to Twitter staff on the news of the CEO changeover, writing in a tweet, “Deep gratitude for @jack and our entire team, and so much excitement for the future.”