In the aspect of excess revenue, the in-sample has great excess returns, the out-sample has negative excess returns, which have shown no market efficiency in China's futures market.

This policy had already had the effect of making interest rates negative, in the very practical sense that UBS was charging institutional customers who held excess deposits in their accounts.

'the excess of optimism is dangerous and could lead to disappointment the first time there is a negative number,' Brazilian central banker Henrique Meirelles told a conference in recent days.