16 See Gorton, G. and Ordoñez, G. (2013), “The Supply and Demand for Safe Assets”, NBER Working Paper, No 8/9  BIS central bankers' speeches  18732, January. 17 For a discussion of the global supply and demand for safe assets, see IMF (2012), “Safe assets: Financial  system cornerstone?”, Global Financial Stability Report, Chapter 3, April.
18 See Brunnermeier, M. (2016), “ESBies: Safety in Tranches”, ESRB Working Paper Series, No 21, September. A  related initiative in the private asset universe is the creation of “simple, transparent and comparable” securitisation, which can produce senior tranches with the characteristic of safe assets.