Three issues were thrown open for debate as a result of the August exchange rate reform, which has changed people's expectations

At the beginning of 2015, no one would have expected the renminbi's exchange rate to become key to China's macroeconomics. Before August, the renminbi's exchange rate changed gradually, appreciating by about 2 percent every year, and its volatility was around 2.5 percent.

But the exchange rate reform on Aug 11 has totally changed people's expectations. China's central bank obviously doesn't want the market to follow the point position or the depreciation rate - it wants the market to follow a fluctuation range.

After Aug 11, the central bank and speculators engaged in many rounds of battle in the foreign exchange markets. We could see their divergence on exchange rate issues, and then make our judgments. As a result, several issues have been up for debate.

First issue: Is China's trade surplus sustainable?

From January to November, China's exports saw a year-on-year decline of 3 percent, while imports saw a year-on-year decline of 15.1 percent. Since July, every month's data has been worse than predicted, so there are many voices in the market saying that the renminbi should depreciate, so as to boost exports.

We have done research that shows the exchange rate elasticity of China's trade exports is gradually falling.