Doesn't anyone notice the Swiss franc's state??
Anybody that's ever been to Switzerland will tell you prices are ridiculous, making Oslo look like package holiday territory. And it has gotten worse recently... The last two years the Swiss franc has gone up by some 60%.
So if you're paid in Swiss francs but are an expat, then you're funnelling off quite a lot into Euros or Pounds, and have in effect had a giant payrise. [Example: work in Geneva, live in France (easily just 25min away from the diplomatic zone) -- so you pay mortgage/rent in Euro, food in Euro, council tax in Euro, ... . Bingo!] So a 10% cut in a tough jobmarket is not such a difficult choice [but 24h decision time is inhumane, human rights court territory].
Conversely, UBS charging for their services in Swiss francs: they've eaten deeply their competitive edge through no management decision of their own.
This of course only holds for Swiss units, not London-based ones.