Beijing will extend to the entire nation a value-added tax on oil and natural gas sales that has been on trial in the Xinjiang Autonomous Region since last year, Bloomberg reported. The tax, which the government said will be between 5% and 10% of sales volume, is intended to encourage energy conservation and boost local government revenues. A 5% tax has been levied on oil and natural gas sales in Xinjiang since June 2010. The new regulation may dampen profits at state-owned energy giants PetroChina (PTR.NYSE, 601857.HKG, 0857.SH) and Sinopec (0386.HKG), the listed arm of China Petroleum & Chemical Corp. The government also said in a separate statement that it may apply a similar tax to other commodities in the future. Qiu Xiaofeng, an analyst at Beijing-based Galaxy Securities, said the government is likely to apply the same 5% tax rate used in Xinjiang nationwide. “A 10% rate would be too heavy,” Qiu said. PetroChina fell 1.4% in Hong Kong yesterday, while Sinopec slid 4.4%.