Twitter CEO Jack Dorsey will leave the company he co-founded a decade and a half ago, according to a statement released by the company on Monday. Dorsey will remain a member of the board until his term expires at next year's stockholders' meeting, according to the firm. Parag Agrawal, a board member and former chief technology officer, has been named CEO, starting immediately. Dorsey co-founded Twitter in 2006 with Evan Williams, Biz Stone, and Noah Glass, and was its CEO until 2008. After former CEO Dick Costolo stepped down in 2015, he returned to the job of CEO. According to Forbes' real-time tracking, he has a net worth of around $11.8 billion. Dorsey warned about the dangers of a firm founder staying on for too long. "There's a lot of talk about the importance of a company being 'founder led'," Dorsey said in an email to employees shared on Twitter Monday. "Ultimately, I believe that's severely limiting and a single point of failure. I've worked hard to ensure this company can break away from its founding and founders." Dorsey's digital payments startup, Square, is still led by him. He is the first individual to have served as CEO of two publicly traded corporations with market capitalizations over $5 billion. "He's been my choice for some time given how deeply he understands the company and its needs," Dorsey explained. "Parag has been behind every critical decision that has turned this company around." He also voiced his faith in Bret Taylor, the incoming independent board chairman. "He understands entrepreneurship, taking risks, companies at massive scale, technology, product and he's an engineer," Dorsey said. "All of the things the board and the company deserve right now." In addition, he praised the Twitter team's desire and promise. Dorsey made no mention of Square or investor pressure on him to choose one of the executive positions in his statement. "I want you all to know that this was my decision and I own it," Dorsey said. "It was a tough one for me, of course. I love this service and company." Dorsey leaves Twitter after a five-year tenure as CEO, during which he helped grow the company's user base and oversaw the installation of a number of new features to broaden the company's reach and combat challenges like abuse and disinformation. Last year, the investment firm Elliott Management began a campaign to oust Dorsey as CEO.