China could be a US$10 trillion economy within 15 years because of restructuring and the creation of market-supporting institutions, predicts Morgan Stanley Dean Witter economist Andy Xie. 'It will probably take place within two decades and could happen in 15 years,' Mr Xie said. The United States economy crossed the US$10 trillion mark last year, he said, while China's hit US$1 trillion. 'However, we believe that China will be the next economy to reach US$10 trillion in today's dollar terms,' Mr Xie said. 'We believe that China's restructuring is real and is greatly facilitated by the application of information technology. ' IT could be key to creating an efficient tax-based system, he said. China could realise its full potential from its scale, high savings rate and low base in an unfettered growth environment. In a report on the mainland's growth potential, Mr Xie said the path to a middle income economy by 2020 was convergence - high economic growth accompanied by real currency appreciation for a decade or more. Poorer countries needed undervalued currencies to offset structural inefficiencies and the high demand for jobs. 'When restructuring has removed most inefficiencies and the employment rate is sufficiently high, a developing economy will become a converging economy,' Mr Xie said. China was expected to experience an even faster rate of convergence during 2005 and 2020 than Japan's economic expansion from 1955 to 1974. Also, China understood the need to share its upside with the global community to align interests for its development. Joining the World Trade Organisation was one practical step. Multinationals controlled about 10 per cent of China's economy and this could hit 20 per cent in five years. However Mr Xie concluded there were 'bear cases' against such a development of the mainland's economy, including social instability, corruption, damage to the environment and containment by developed nations. Investors seeking a guide to when a structural 'bull case' would unfold should wait for, firstly, China's entry into WTO, he said. The next milestone was the separation of businesses and government.