In such a case, there is a possibility that the central bank’s purchase of risk assets will lead the central bank to play a role as a “catalyst” to alleviate the tendency of excessive risk aversion. For reference, please see Nishimura, K.G., and H. Ozaki, “Irreversible Investment and Knightian Uncertainty,” Journal of Economic Theory, 136 (2007), 668–694.
4  For the purchases of ETFs and J-REITs, the Bank needs to seek approval from the government and it will do so in due course. 4  BIS Review 137/2010  receive.