Royal Dutch Shell's new boss Ben van Beurden today admitted the oil giant's performance was "not what I expect" from the group in 2013 as he issued a shock profit warning just two weeks after taking over at the helm.
Mr Van Beurden - who succeeded Peter Voser as chief executive on January 1 - said the firm's fourth quarter figures were expected to be "significantly lower than recent levels of profitability".
Its fourth quarter underlying earnings are now expected to almost halve to around 2.9 billion US dollars (£1.8 billion).
This is set to leave full year results 23% lower at 19.5 billion dollars (£11.9 billion).
Mr Van Beurden said: "Our 2013 performance was not what I expect from Shell."
Shell blamed lower oil and gas prices and "weak industry conditions" in downstream oil, as well as higher exploration expenses and lower upstream volumes.
Its recent third quarter figures were hit badly by a 49% drop in downstream profits as a result of weaker refining conditions caused by industry overcapacity and weak demand.
The group also said today it expects hefty writedowns of 700 million dollars (£429 million) for the fourth quarter and 2.7 billion dollars (£1.7 billion) for the full year relating to its its upstream business.
These are expected to hit results even further, sending fourth quarter earnings 70% lower to around 2.2 billion dollars (£1.3 billion) and 2013 earnings 38% down to about 16.8 billion dollars (£10.3 billion).
Mr Van Beurden said: " Our focus will be on improving Shell's financial results, achieving better capital efficiency and on continuing to strengthen our operational performance and project delivery."
The group will report full-year results on January 30.
Shares fell 4% after the profit alert, which comes after an already disappointing past few months for the Anglo-Dutch group.
Former chief Mr Voser warned in October that Shell was "entering into a divestment phase" as he reported a worse than expected slump in third-quarter profits.
It marks a gloomy start to Mr Van Beurden's tenure at the group.
The Dutch national had risen through the ranks over three decades before securing the top post, beating off competition from internal and external candidates.
He joined the Shell group of companies in 1983 and has held a number of technical and commercial roles in both the upstream and downstream businesses, including in London.
His predecessor Mr Voser, who had been chief executive of Shell since July 2009, announced plans to retire from the role in May to pursue a "lifestyle change", telling staff he wanted to spend more time with his family.
Oil analyst Neill Morton at Investec Securities said Shell had never before issued a profit warning ahead of its full-year earnings.
He added: "Shell has broken with its recent custom of disappointing on earnings day - it is now dishing up the bad news ahead of time."
Rival BP also saw shares come under pressure as the market feared an industry-wide impact.
The entire sector has already been suffering from low refining margins - how much money is made from processing crude oil into petrol and diesel.
Neil Shah, analyst at Edison Investment Reserch, said: "The weaker refining conditions Shell faces may just point to an economic recovery that is far more patchy than most expect.
"If Shell catches a cold the rest of the oil sector will always wonder if they will catch flu."