China's largest oil refiner's plan to seek social and private capital highlighted the country's endeavors to forge a mixed ownership economy amid further opening-up expectations. Sinopec, one of China's three oil giants, proposed on Wednesday to sell up to 30 percent of its multi-billion dollar marketing arm to social and private investors. The stake sale plan was the first move a stated-owned enterprise administered directly by the central authorities (centrally administered SOEs) shared lucrative business with private investors. Sinopec's marketing division operated 30,532 gas stations across the country as of the end of 2013, and fuel sales stood at 165 million tonnes last year. China's important sectors are largely dominated by 112 centrally administered SOEs, but the public complain about low efficiency and high welfare mainly resulted from monopoly. To unleash the vigor of a market economy, the Communist Party of China vowed last November to actively promote mixed ownership and raise non-state share in the economy. "Sinopec's move is a solid reflection of the central authorities' determination," said Zhang Chunxiao, an expert with the State-owned Assets Supervision and Administration Commission (SASAC). Li Jin, chief researcher of China Enterprise Research Institute, called the plan "a big step taken by centrally administered SOEs in breaking monopoly and developing mixed ownership".