18 In this sense, considerations related to the introduction of universal reserves are also linked to the parallel  discussion on the future size of central bank balance sheets, where some academics argue that central banks should keep balance sheets close to current levels in an effort to promote financial stability by providing a safe asset (see, for example, Greenwood, R., S. G. Hanson and J. C. Stein (2016), “The Federal Reserve’s Balance Sheet as a Financial-Stability Tool”, paper prepared for the 2016 Economic Policy Symposium Proceedings, Jackson Hole: Federal Reserve Bank of Kansas City).
19 For an illustration of this risk in relation to the Swiss “Vollgeld” initiative, see Jordan, T. (2018), “ Why sovereign  money would hurt Switzerland”, speech at the Swiss Institute of Banking and Finance at the University of St. Gallen, Zürich, 3 May. 20 See, for example, ECB (2017), “Report on financial structures”, October. 21 See Cœuré, B.