PETROCHINA Co, Asia's biggest oil company, may say profit dropped for the first time in five years after the government raised taxes and oil prices fell.

Net income probably slipped 2.2 percent to 78.9 billion yuan (US$10.4 billion) in the six months ended June 30, according to the median estimate of 11 analysts in a Bloomberg News survey. Beijing-based PetroChina reports its results today. Jiang Jiemin, appointed chairman in May, may show the first drop in earnings since 2002 after China introduced a tax that takes effect when oil exceeds US$40 a barrel. A two-percent slide in crude prices will also hurt the result, as it did for Exxon Mobil Corp, Royal Dutch Shell Plc and BP Plc, the three largest publicly traded oil producers by sales.