Twitter Inc. ( TWTR ) reached an agreement with activist investors Elliott Management and Silver Lake Monday, and pledged to buyback $2 billion in stock, in a pact that likely keeps co-founder Jack Dorsey as CEO. Twitter said the agreement includes a $1 billion investment from Silver Lake, that will partly fund the buyback, while Elliott, which owns a 4% stake in the mico-blogging site, will place managing partner Jesse Cohn, along with Silver Lake's Egon Durban, onto Twitter's executive board. The agreement, however, also pledged "evaluate the CEO succession plan" with Dorsey and "and make recommendations consistent with corporate governance best practices with respect to the elimination of the Company's staggered board." "Twitter serves the public conversation, and our purpose has never been more important. Silver Lake's investment in Twitter is a strong vote of confidence in our work and our path forward," said CEO Jack Dorsey.