Simon Lowth is to quit as chief financial officer at AstraZeneca and return to his energy roots in the same role at BG Group after being passed over for the top job at the drugmaker.

Lowth, who will be 52 in August, is leaving one company faced with a turbulent financial future for another. BG's challenge is to recover from last year's announcement that it would miss output targets and the abandonment in February of longer-term production goals. Investors are also fretting about its exposure to strife-torn Egypt, home to a fifth of the company's production on which cash flow for costly future projects depends.

AstraZeneca also faces difficulties. Chief executive Pascal Soriot told Reuters in June that turning around the drugmaker would be a long haul as it battles falling sales due to patents expiring.

Lowth cut his managerial teeth at the privatised utility Scottish Power between 2003 and 2007, where he rose through the ranks to become finance director, before he moved to AstraZeneca as chief financial officer. He was named interim chief executive in June last year after repeated drug development setbacks and investor discontent over performance cost David Brennan his job at the company.

Speculation he might leave has been circulating since Soriot was poached from rival pharmaceuticals group Roche Holding and took on the permanent CEO role in October last year, meaning Lowth returned to his role as finance chief. Lowth will replace BG's interim chief financial officer Den Jones, who has been holding the fort since February after Fabio Barbosa fell ill. Barbosa has since retired.

'Intense, Driven'

BG, which like Scottish Power is formerly state-owned, also has a new CEO, Chris Finlayson. Lowth will help Finlayson with the company's focus on driving profit growth through its exploration and liquefied natural gas businesses and on selling or partnering on more of its discoveries.

"He brings with him a great combination of finance, capital allocation, value-based planning, portfolio management and strategy skills - critical skills as we execute our strategy to deliver long-term value to shareholders and focus on excellence in execution," Finlayson said in a statement.

Lowth, who worked from 1987 to 2003 for management consultancy McKinsey, took on the job of finance director at Scottish Power after the company's decision to back out of its unsuccessful U.S. acquisition, PacificCorp. "He's a very intense, driven man - a technical strategy type I would say," said a former colleague.

AstraZeneca said the search for a replacement for Lowth was underway. Lowth will forfeit his AstraZeneca bonus for 2013 but BG, which will pay him a base salary of £725,000 ($1.10 million), will compensate him for it. He was paid a cash bonus of 1.034 million pounds last year. He is to leave AstraZeneca in October but as yet has no official start date at BG.

His base pay at BG is higher than his £660,000 AstraZeneca finance director salary, but below the £900,000 rate he was earning while he was in the interim CEO role.