In an earlier call with investors, he said the review would have "no constraint".
Immelt, 61, succeeded legendary CEO Jack Welch, who led the company for 20 years and vastly increased its size and scope. Immelt, an avid golfer, became a founding member of the private club off River Road in 2001.
In his view, Flannery's prior experience leading GE's business development team, which seeks out M&A deals, would make him "readily adept at maximizing value and structuring potential exits" - as Flannery did through the 2015 acquisition of Alstom's power and grid business.
Flannery's GE bio touts his leadership of the company's healthcare wing. "We're not starting from a weak position at all".
Shares of GE jumped 3.6% to close at 28.94 on the stock market today, retaking their 10-week moving average for the first time since late April.
According to his GE biography, Flannery "is a graduate of Fairfield University and holds an MBA from the Wharton School at the University of Pennsylvania". In our view, the balance of delivering near-term results while positioning the business for the long haul is a trade-off that Flannery knows well from his recent role in GE Healthcare.
Despite investing heavily on developing digital products, from sensors in jet engines to augmented reality software, shareholders have been wary of the company's new direction.
Since Immelt became CEO, GE's shares have declined 30 per cent, while the S&P 500 index more than doubled. "The market didn't want to give Immelt any credit for those investments because so numerous things in the past haven't worked out". He outlined Trian's thinking on how the industrial giant could achieve profit of as much as $2.33 a share in 2018 if it delivered on promised cost cuts, kept on its existing growth path and stabilized the oil and gas business.
Immelt was onsite at the groundbreaking for Boston's GE headquarters last month, alongside Mayor Marty Walsh and Gov. Charlie Baker.
Mr Immelt said he'd been planning for several years to step down around now, and the final agreement came at last Friday's board meeting.
The change at the top is not surprising given the ongoing underperformance of the stock and "investor fatigue with management's continued perceived ungainly portfolio actions", says Stifel analyst Robert McCarthy. "I think the timing is flawless for the new CEO coming in to continue these investments and increase the value of GE's business". On Monday, GE reached a deal with US regulators to win approval of its purchase of oilfield service giant Baker Hughes.