This – along with the SNB’s willingness to intervene in the foreign exchange market – has helped to relieve pressure on the Swiss franc. The effect of the negative interest rate on the exchange rate is currently playing a decisive role in enabling the SNB to fulfil its monetary policy mandate. It allows the SNB to counter the aforementioned consequences of the Swiss franc appreciation on economic developments and inflation. Without the negative interest rate, inflation and economic growth in Switzerland would be lower. 3  Low interest rates and Swiss banks’ profitability The negative interest rate thus remains indispensable from a monetary policy perspective, and has, as explained, achieved the desired effect. A monetary policy geared to price and economic stability is also a precondition for a profitable, stable financial system. An environment of decreasing prices and low growth would lead to reduced demand for banking business and increased credit defaults, losses and write-downs. At the same time, the exceptionally low interest rates are fraught with significant challenges. Above all, over time they can have economically undesirable consequences for financial stability. We have arrived at the main topic of my remarks today, namely, how does the SNB assess the effects of low interest rates on financial stability? The answer to this question largely depends on the extent to which low interest rates affect banks’ profitability.
A second – and important – explanation can be seen in the red shaded area of this chart (slide 8). Domestically focused banks have reacted to the decline in liability margins by increasing asset margins by around 50 basis points. Specifically, following the introduction of negative interest, they raised rates for long-term mortgages (shown here in blue), while returns on long-term market investments (illustrated here using the ten-year swap rate in yellow) continued to fall. The banks have since managed to keep asset margins high, notwithstanding the fact that market rates have continued to decline. But there is another, equally important explanation for the limited impact of the low interest rate environment on the profitability of domestically focused banks: these institutions have increased their risk appetite. This applies particularly to affordability risk (typically measured using the loan-to-income ratio) in lending and to interest rate risk from maturity transformation. Let’s take a closer look at the current risk situation with respect to domestically focused banks in Switzerland. Affordability risk refers to cases in which a borrower can no longer afford to make interest and amortisation payments for a loan under unfavourable conditions. 5 A representative quarterly survey conducted by the SNB indicates that a substantial share of new mortgages exhibit high loan-to-income ratios. Moreover, this share has been rising since 2013. 6 Put simply, interest rate risk is the risk that banks will suffer losses as a result of rising interest rates.