SNB rate - FED rate = hedging cost for CHF/USD. To be exact it’s actually the difference between short term state bond rates (1 year for example).
Btw, an overweight to Swiss stocks isn’t really that bad. It had an avg. return of 8-9%/year in the last couple decades (see MSCI Switzerland). So in CHF even better than the SP500. My personal take: Switzerland will keep outperforming the rest because of several factors. We are very similiar to the US (high inflow of skilled workers, a lot of high tech companies, low taxes for companies etc.) but have several advanptages like a more stable political system, free schools, high median salary, basically no poverty, no war and pretty good relationships with the rest of the world (US, China and Russia). This might be priced in already, but I’m willing to take the bet and set CH to 37%.