Royal Dutch Shell says fourth-quarter earnings tumbled 44 percent as the collapse in oil prices took its toll on another European oil company.

The Anglo-Dutch energy giant said Thursday that profit adjusted for changes in the value of inventories and one-time items dropped to $1.83 billion from $3.26 billion in the same period a year earlier.

The results came days after Shell sealed a 47-billion-pound takeover of BG Group Plc, which will increase the company's proven reserves of oil and natural gas by 25 percent.

While critics questioned the deal because of the plummeting price of oil, CEO Ben van Beurden compared it to the bold moves that have defined the industry and promised it would rejuvenate Shell.