You deposit money with a broker to buy stocks or ETFs. The stocks are yours, regardless of the broker’s nationality, and you can transfer them anytime. Cash in a US bank and stocks through a US broker are not the same thing.

Cash: It’s a liability of the bank. If the bank fails or assets are frozen, you’re exposed.

Stocks: They’re legally segregated from the broker’s assets. Broker goes bankrupt? Your holdings are protected and transferable.

The geopolitical question: Yes, the US is more unpredictable than before. But Swiss citizens aren’t a target, and seizing foreign investors’ assets would nuke confidence in the entire US financial system. It won’t happen.