In Wieland's opinion it is not necessary to limit the citizens' access to cash, let alone to lower the interest rate floor even further. Monetary policy remains powerful despite the interest rate floor as demonstrated by Wieland's research. In spite of the interest rate floor the central bank is able to reach its objectives by quantitative easing. These policy easing measures imply an expansion of the central bank's balance sheet, e.g. by direct purchase of securities.
Zeitschrift für das gesamte Kreditwesen: Overview 14/2016
Speech by Volker Wieland on "The role of cash in monetary theory and monetary policy" (PDF, 69 KB) (German)