Oil and gas giant PetroChina plans to sell up to US$8.67 billion in bonds to optimize its debt structure and boost working capital, the Wall Street Journal reported. The bond sale would be the largest ever by a listed company in China. It would represent a significant step forward for the country’s relatively undeveloped corporate debt market. Analysts said the new capital will help PetroChina reduce financing costs at time when it faces huge refining losses due to rising oil prices. PetroChina said it had received board approval to issue the bonds and would now seek the support of shareholders as well. The bonds will have a maturity of up to 15 years. Yields on 15-year bonds issued by large state-owned companies traded at 4.83% Wednesday. The 15-year loan rate is 7.83%.