China's stock market (the "A share market'') has a lower correlation with the global market and is less affected by international financial contagions than any other major economy. The inclusion of mainland China stocks into an international portfolio increases its Sharpe ratio. However, we find that Chinese stocks providing the most diversification benefits also carry the most policy risk for international investors. Holding Chinese stocks listed in Hong Kong does not reap the same diversification benefits. While global market integration and the increase in foreign ownership can diminish diversification benefits, mainland China stocks still provide valuable diversification opportunities for international investors up till the most recent time in late 2010s.

Our study is the first to examine the effect of policy instability on interest rates. China offers a natural setting for the experiment because financial market liberalization policy flip-flops recur. When a policy is reversed, interest rate level and spread can increase or decrease in the interbank repo market. Accounting for the bureaucratic quality of policymaking, we find that the nonpredictable, non-credible and non-timely reversal of an existing policy is related to higher interest rate spread and volatility, which represent higher risk premia in interest rates. Conversely, predictable, credible and timely reversal is related to lower interest rate spread and volatility. Our results suggest that bureaucratic quality is a moderating factor and high bureaucratic quality can reduce the risk premia of policy instability being priced in interest rates.