Overnight rate and signalling effects of central bank bills

We analyse the impact of interest-bearing central bank bills on financial market variables in Switzerland. The unique institutional setting allows us to identify the causal effects of two orthogonal shocks occurring on days with central bank bill auctions through heteroscedasticity: an overnight interest rate shock and a signalling shock. The first shock raises the overnight interest rate and modestly appreciates the exchange rate. The signalling shock appreciates the exchange rate more strongly. In addition, it lowers stock prices, long-term interest rates, as well as inflation expectations, and it raises corporate bond spreads. The signalling shock is economically more important for forward-looking variables than the overnight rate shock. The results suggest that liquidity-absorbing operations between official monetary policy decisions affect financial market variables by revealing information about the central bank’s future policy actions.