This paper investigates the speed and completeness of the pass-through from market rates to mortgage rates in Switzerland. The pass-through dynamics are studied under a marginal funding cost perspective. By choosing the appropriate benchmark rates, this study takes into account banks' forecasts of the evolution of their funding costs. It is found that the passthrough of rates of adjustable-rate mortgages is incomplete and sluggish compared to the rates of mortgages with a fixed maturity. For the latter, changes in market rates appear to be transmitted quickly and completely, particularly when benchmark rates are falling. This finding suggests that a low-interest-rate environment stimulates competition among financial institutions. Evidence for a structural change is found for all interest rates. The structural change occurred around the beginning of 2007 for fixed-rate mortgages and in mid-2005 for floating-rate mortgages. For all mortgage rates, asymmetries are detected in the pre-break period. More specifically, the adjustment of fixed-rate-mortgage rates is characterized by downward rigidity, which supports the existence of some form of imperfect competition. By contrast, the rates of adjustable-rate mortgages exhibit upward price stickiness. This result suggests that competition was stronger in this specific mortgage-lending market. In the post-break period, no clear evidence is found in favor of asymmetries with respect to the adjustment coefficient.