China’s economic planning agency, the National Development and Reform Commission (NDRC) is leading talks on spinning off oil and gas pipeline assets from Sinopec and PetroChina Pipelines into independent businesses, according to people familiar with the plan.

China National Petroleum Corp. and its listed arm PetroChina Co. is the country’s biggest owner of pipelines, controlling about 77,000 kilometers (48,000 miles). China Petrochemical Corp. and its listed unit China Petroleum & Chemical Corp., or Sinopec, are the next largest with more than 30,000 kilometers.

The assets could be worth as much as $300 billion, according to an estimate by Neil Beveridge, a Hong Kong-based analyst at Sanford C. Bernstein.