The world's richest person Elon Musk is the largest shareholder of Twitter, owning a 9.2% stake in the platform. Vanguard Group is the second-largest shareholder, with an 8.4% stake, followed by Morgan Stanley Investment Management (8.1%), BlackRock (4.6%) and SSgA Funds Management (4.5%), according to FactSet. Aristotle Capital holds a 2.5% stake and Co-founder Jack Dorsey holds a 2.3% stake.