Chinese investors rushed to buy bitcoin after the shutdown of the Mt Gox exchange caused a fall in the value of the virtual currency this week, South China Morning Post reported. Since Tuesday, more than 30,000 bitcoins have changed hands in China, which is four times the usual trade volume, and compares with just 300 exchanged in the United States. Chinese investors see the virtual currency as potentially undervalued, marking a strong return to the market after the People’s Bank of China moved to cool interest in bitcoin.