Abu Dhabi's International Petroleum Investment Co. will buy a 20.85 stake in Cosmo Oil Co. of Japan, expanding in Asia's second-biggest fuel market, Cosmo Oil said Tuesday.

Infinity Alliance Ltd., wholly owned by IPIC, will pay ¥89.2 billion for 176 million new Cosmo shares, the company said in a statement to the Tokyo Stock Exchange. The Abu Dhabi investment agency will become Cosmo's largest shareholder.

Record oil prices have bolstered revenue in oil-producing nations, prompting acquisitions of refineries as Asian energy demand increases. Earlier this year, Abu Dhabi paid $220 million to boost its stake in Hyundai Oilbank, South Korea's fourth-biggest refiner, to 70 percent from 50 percent. In 2004, Saudi Arabia's state oil company bought a 14.96 percent stake in Showa Shell Sekiyu K.K., the Japanese unit of Royal Dutch Shell PLC.

"Oil money is driving the appetite for refining assets," said Hirofumi Kawachi, a senior energy analyst at Mizuho Investors Securities Co.

"Middle East nations are acquiring Japanese refineries in a bid to boost petroleum exports to China, one of Asia's economic powerhouses," Kawachi said.