Royal Dutch Shell Plc has surpassed Chevron Corp. as the world’s second-biggest non-state oil company after completing the acquisition of BG Group Plc.

The purchase raises Shell’s market capitalization to $177 billion and adds new assets in Australia and Brazil that give it more flexibility to ride out a downturn, Barclays Plc said in a report Monday.

Exxon Mobil Corp. remains the world’s most valuable oil company with a market value of $337 billion, almost twice as big as Shell.