Ubben will become the chairman of the company and continue to oversee ValueAct Spring Fund, which invests in companies aiming to address environmental and social problems, the source said.
Separately, Brandon Boze, a partner and member of the company's management committee, was promoted to the role of president, Morfit said in a statement.
The Financial Times first reported that Ubben is stepping down as CEO.
(Reporting by Manojna Maddipatla and in Bengaluru, additional reporting by Bharath Manjesh; Editing by Anil D'Silva and Aditya Soni)
By Svea Herbst-Bayliss