thoughts anyone? SHANGHAI (Reuters) - The Chinese authorities have raised the stamp duty on share trades to 0.3 percent starting on Wednesday from the current 0.1 percent, a move seen as a bid to clamp down on the overheated market. China's Ministry of Finance made the midnight announcement through the official Xinhua news agency, an unusual move that underlined deep government concerns after the key stock index (.SSEC: Quote, Profile, Research has risen 62 percent so far this year on top of a 130 percent jump last year. The index has hit repeated record highs this month. In the 16-year history of the modern Chinese stock market, an increase in stamp duty has always caused a market slump over the following few weeks or ended a bull run.