The cause of capital outflows

Capital outflows have become a problem of the current Chinese economy. What are the causes of capital outflows? Firstly, the balance of payment is always zero in theory. If the current account is in surplus, then the capital account will be in deficit. Secondly, if the returns of capital overseas are higher, capital tend to outflow. Thirdly, if the domestic risks become higher, investors will try to move their capitals to foreign countries to avoid risks. Fourthly, when the costs of transferring capitals become cheaper, it will speed up capital outflows.