UPDATE 1-Vanguard exec who oversaw $1 trillion in assets resigns

Jan 3 (Reuters) - Vanguard Group, the No. 1 mutual fund company, said on Thursday that Sandip Bhagat, the head of a global equity group that oversees about $1 trillion in assets, has resigned.

No replacement was named. Bhagat's departure came as Tim Buckley takes over as Vanguard's chief investment officer this month. Buckley replaced long-time CIO Gus Sauter, who is retiring.

Bhagat, who oversaw all passive, exchange-traded funds and active stock portfolios, left the company to pursue other opportunities, Vanguard spokeswoman Linda Wolohan said.

"The leadership of the Equity Investment Group, which oversees the management of roughly $1 trillion in assets, is expected to be formally announced soon," Wolohan said in an email.

The announcement of Bhagat's departure was contained in a supplement to a prospectus filed with the U.S. Securities and Exchange Commission. The filing mostly centered on the expected retirement of Sauter.

Bhagat's departure received one line.

"Also, Sandip A. Bhagat has resigned as head of Vanguard's Equity Investment Group," Vanguard said in the filing.

Before joining Vanguard in 2009, Bhagat was head of global asset allocation and systematic strategies at Morgan Stanley investment management. He began his career in 1987 at Travelers Investment Management Co and eventually became its chief investment officer.