alefsin: as far as I understand, the US will withhold some tax, and you'll have to file a tax return in the US. However, since you'll be a non-resident, the tax shouldn't be very high and you'll get some money back. You probably will not have to pay the Social Security and other insurances.

How does one pay taxes in Switzerland in such case? A person on a B permit earning less than 120K pays taxes at the source, and can't file a tax return. Is this correct? How can I pay Swiss taxes without filing a return? (I'm in a similar situation to the OP).

Another question is about the work permit. Is it even allowed to work for a foreign employer while waiting for B permit to be processed? It seems wasteful to prevent people from doing something useful and bringing money to the country without taking anyone's job (in Switzerland), but these things are often illogical.