U.S. industrial conglomerate General Electric Co.'s chairman Jeff Immelt retired earlier-than-expected on Monday, with the company naming Chief Executive John Flannery as his replacement.

Immelt, who was expected to retire by the end of this year, had resigned as GE's CEO in June amid amounting pressure from activist-investor Nelson Peltz's Trian Fund Management for operation changes.

GE said Immelt also retired as director and chairman of the board of directors of Baker Hughes, a GE company.

Baker Hughes' CEO Lorenzo Simonelli will succeed Immelt as chairman of the company's board.

W. Geoffrey Beattie was also appointed as lead independent director at Baker Hughes, GE said.

Beattie was CEO of the Woodbridge Co, the Thomson family company that controls news and financial information provider Thomson Reuters Corp.