BP Plc (BP.N) joined its Big Oil peers by giving investors a positive surprise, exceeding fourth-quarter profit estimates as rising output and refining throughput offset the impact of a slump in crude prices.

The better-than-expected earnings should give shareholders some comfort after BP took on more debt to pay for a swath of U.S. shale assets, its biggest deal in 20 years. The company has shown more “flexibility” than its peers as it seeks to snap up assets and boost production, Colin Smith, an analyst from Panmure Gordon & Co. Plc, said before the earnings.

Six major projects started up in 2018 and oil and gas output rose 2.4 per cent to 3.683 million barrels of oil equivalent a day, the first of several years of forecast growth.

“We now have a powerful track record of safe and reliable performance, efficient execution and capital discipline. And we’re doing this while growing the business,” Chief Executive Officer Bob Dudley said in a statement on Tuesday. “Our strategy is clearly working.”

The London-based oil major said adjusted net income was US$3.48 billion in the fourth quarter, beating analyst estimates of US$2.64 billion. Profit for the full year was US$12.72 billion, as high as when oil was trading close to US$100 a barrel.

BP faces a trickier balancing act between output growth with financial discipline than some of its peers. It’s still recovering from the 2010 Deepwater Horizon catastrophe, which killed 11 people and cost it more than US$60 billion in penalties and compensation.

Last year, BP purchased US$10.5 billion of shale assets from BHP Billiton Ltd., paying entirely in cash. It plans to sell as much as US$6 billion of older U.S. onshore fields to reduce debt accrued in the purchase. The company exceeded its US$3 billion divestment program for 2018.

Gearing, the ratio of net debt to total equity, rose to 30.3 per cent last quarter, the highest level in at least a decade. BP has said indebtedness will fall as new projects come online and cash flow rises.