Swiss companies have already invested USD 27 bn in the American economy this year.
The investments are meant to keep US import tariffs on Swiss goods at 10%, after they were threatened with rising to 39%.
Novartis, Roche and shipping group MSC are among the firms expanding US production and headquarters.
But Washington has now added a 2.5% surcharge on countries it accuses of weak action against forced labour, a list that includes Switzerland.
Bern disputes the claim and is pushing for a renegotiated trade deal to head off further escalation.
Border closures and checks start today
French strike hits train services
Geneva votes to ban religious symbols
The US is not seen as reliable
Heatwaves becoming more normal
The lynx return remains vulnerable
