Mellody Hobson, president of Ariel Investments, has been promoted to co-ceo, V.P. Martin Gawne confirmed.

Hobson is now responsible for all firm-wide management, including strategic planning and growth as well as Ariel’s business beyond research and portfolio management, according to her biography on the firm’s website. She will continue to serve as president.

She will work alongside John Rogers, who has become co-ceo and will continue to manage Ariel’s flagship domestic equity portfolios and serve as cio and chairman, the firm said.

Additionally, Hobson will purchase approximately 14% of Rogers’ holdings and own 39.5% of Ariel, with Rogers owning 34.1%, upon the transaction’s expected close on July 19, according to Rogers’ letter to clients yesterday.

“Both her promotion as well as this share purchase represent a long-planned generational transition of leadership and ownership while simultaneously allowing us to maintain continuity,” Rogers said, in the letter. “As many know, I have never been a seller of my Ariel stock and these are the only shares that I ever plan to sell.”

Rogers plans to manage Ariel’s stock portfolios for “at least another decade—if not more,” he added.

Hobson joined Chicago-based Ariel in 1991 as a member of the firm’s client services and marketing team and was subsequently named president in 2000, Gawne confirmed.

Ariel has approximately $13 billion in total assets under management, the firm said.