...Will the rate cut of the SNB lower the domestic interest rate level in Switzerland even further?
Maybe yes, maybe no. One argument is, if you lower the rate set by the central bank, then all the other rates will follow. My reaction is: Not so fast, my friend! The Swiss banks are now suffering losses on their reserves at the SNB. Banks could reduce interest rates on deposits to recoup these losses. But this has clear limits: People do not have to hold money at banks, they can ask for their money in notes. The banks could also recoup their losses in a different way, and this is something to be concerned about: They could raise the rates on loans. Far from encouraging lending and spending, negative interest rates at the central bank might work in the opposite direction.