China’s central bank has widened its questioning of domestic bitcoin exchanges, after prices of the virtual currency have continued to gain, hitting a one-month high, despite efforts by authorities here to clampdown on trading. Officials from the People’s Bank of China in Beijing met with nine small bitcoin platforms Wednesday afternoon, The Wall Street Journal reports. The meeting comes after the bank found improper practices at China’s three largest bitcoin exchanges in January. Questions from the meeting included but weren’t limited to anti-money-laundering. Analysts say that bitcoin worries Chinese authorities because of its volatile nature and potential to help Chinese investors move money out of the country. Chinese traders say that the usage of bitcoin is but a drop in the bucket compared to China’s total capital outflows. Prices of the virtual currency soared last year on Chinese demand as Bitcoin became a way for investors to bet on a depreciating Chinese yuan.