Do not choose a broker by trading fee alone
A low trading fee is attractive, but tax reporting can cost time and money. Swiss residents need usable annual statements, income breakdowns, positions, and sometimes data for foreign withholding tax relief.
If a broker makes it hard to identify dividends, withholding tax, fund income, or year-end values, the cheap account may become expensive at tax time.
Expats should also ask whether the broker supports the tax forms they need, including foreign withholding documentation where relevant.
DA-1 and foreign withholding tax
Foreign dividends may suffer withholding tax in the source country. Depending on the country, treaty, and Swiss tax filing, part of that tax may be creditable or recoverable.
In Switzerland, DA-1 is often discussed in this context. The exact process depends on canton, tax software, security type, and documentation. The key point is to keep clean records from the start.
Do not mix this with the Swiss 35% anticipatory tax. Swiss withholding and foreign withholding are different problems, even though both reduce cash received.
Currency risk for mobile professionals
Many expats earn CHF, invest globally, and may retire or relocate in another currency. That is not a reason to avoid investing, but it is a reason to know what currency risk you are taking.
A global ETF may trade in USD, report in another currency, and hold companies earning revenue worldwide. Your broker account currency is only one layer.
A practical portfolio note should say what you earn in, what you spend in, what you may need for relocation, and what currency your long-term goals are likely to use.
Also check whether the broker can export reports in a format that matches your Swiss tax workflow. A portfolio that is easy to buy but hard to report is not really simple for a resident taxpayer.
Before transferring a large portfolio, download a sample annual statement and ask whether it separates income, withholding, positions, and transactions clearly enough for your canton.