The U.S. Financial Industry Regulatory Authority (FINRA) board of governors on Friday unanimously elected John J. “Jack” Brennan, Vanguard Group chairman emeritus and senior advisor, as FINRA chairman.

Brennan has served as FINRA’s lead governor since 2011 and succeeds Richard Ketchum as chairman.

Brennan’s term will be effective upon Ketchum’s previously announced retirement. In June, FINRA announced that Robert Cook will become FINRA’s new chief executive in the second half of 2016; his expected start date is Aug. 15. It was also announced at that time that FINRA would move to a governance structure with an independent chair.

“Throughout his tenure on the boards of FINRA and its predecessor, as well as his many years leading Vanguard, Jack has been a tireless advocate for individual investors and liquid, fair markets,” says Ketchum in a statement. “During my tenure at FINRA, Jack has been a trusted adviser and partner, helping us develop a number of important programs to support our mission.”

“Jack is widely respected throughout financial and regulatory circles as a champion of the individual investor with a commitment to fair, transparent and efficient markets,” adds Cook. “He has an unwavering dedication to FINRA and its mission of investor protection and market integrity. I’m looking forward to a productive partnership with Jack and the entire board of governors.”