Royal Dutch Shell's 54-year old chief executive Peter Voser is to retire next year in a surprise early departure that he said was driven by a desire for a change of lifestyle.
The softly-spoken Swiss national with a quarter century career at Europe's top oil company, has transformed it since 2009 from sector laggard to a leading position in the burgeoning industry of liquefied natural gas (LNG).
But his departure comes as the company and the industry face huge challenges.
Shell is the western world's number two company by production behind Exxon Mobil, but like its peers, it is struggling to replace reserves and boost production, and faces a squeeze on earnings as costs rise while the price of oil threatens to fall decisively below the psychologically important $100 a barrel level.
Analysts say that among the world top oil companies, Shell spends more on exploration per barrel produced than any of its competitors. Its most high-profile exploration failure has been in Alaska where it has spent $5 billion since 2006, and has yet to drill a single complete hole.
Meanwhile thefts, strikes and other issues dog activity in Nigeria where it is the principle international oil company operator.
"After such an exciting executive career I feel it is time for a change in my lifestyle and I am looking forward to having more time available for my family and private life in the years to come," Voser said in a statement on Thursday.
Shell said it would look outside and inside the company for his replacement. A spokeswoman said Shell had looked outside for CEOs in the past. However, as with most big oil companies, new chief executives traditionally come up through the ranks.
The last of the western world's four biggest oil companies to report results, Shell joined its peers in delivering a result that topped market expectations, thanks in part to strong refining and trading performances.
Adjusted net profit on a current cost of supply basis rose to $7.5 billion in the first quarter from $7.3 billion a year ago and compared with expectations of around $6.5 billion.
Shell did not take a writedown on its unsuccessful Alaskan drilling programme as some analysts had expected.
Voser has been named in media reports as a possible chairman of Roche Holding, the drugmaking company based in his native Switzerland and where he is already non-executive director.
Shell had no comment beyond its official statement, but one insider said Voser had indicated he had no plans to take on new non-executive directorships or chairmanships.