(Bloomberg) -- Facebook Inc. appointed Robert Kimmitt, a former deputy Treasury secretary under President George W. Bush, as lead independent director.

The social media company and Chief Executive Officer Mark Zuckerberg have been criticized for Facebook’s corporate structure, in which Zuckerberg has a controlling stake in the company thanks to a special class of super-voting shares. His dominance has been a point of contention for investors who believe Facebook has been irresponsible in the handling users’ personal data, and that Zuckerberg has not been held accountable.

The board’s lead independent director is supposed to provide oversight of Facebook and Zuckerberg for shareholders.

“The lead independent director is an important role for us and we’ve been looking for a leader who can bring significant oversight and governance experience,” Zuckerberg said Thursday in a statement announcing Kimmitt’s appointment.

Kimmitt, 72, replaces Susan Desmond-Hellmann, former CEO of the Bill & Melinda Gates Foundation, as lead independent director. Desmond-Hellmann announced in October she was leaving the board. Jeffrey Zients, CEO of The Cranemere Group Ltd., will also leave the board at Facebook’s annual meeting later this year, the company said.

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