Do I pay German tax on dividends, interest and capital gains from my US brokerage account?

Yes, usually you do if you are a German tax resident. Under the US–Germany tax treaty, dividends, interest and capital gains from investments are taxed where you are resident, which in this case is Germany.  The US can still withhold tax on US dividends, but the main right to tax your portfolio income sits with Germany once you live there.

In Germany, these investment incomes are generally taxed at 25% plus solidarity surcharge, for an effective rate of about 26.4%, after a 1,000 EUR annual allowance.  US withholding tax on dividends (typically 15%) can usually be credited against your German tax bill on the same dividend, so you do not pay tax twice on that income.

A few details matter for US expats in Germany:

• German tax law does not distinguish between short‑term and long‑term capital gains on shares. All gains on shares bought after 31 December 2008 are taxable; only very old positions held since before 2009 can still be fully tax‑free.

• Germany taxes the gain as “proceeds minus acquisition costs”, so you need cost basis information for your US trades in euros, not just in dollars.

• Some US tax‑favored plans (for example certain 401(k) and retirement schemes listed in the treaty) may be treated differently. As long as the assets stay inside a qualifying plan, Germany can in some cases ignore the dividends, interest and capital gains until you actually take money out.

Because the treaty rules and product types are technical, it is easy to make mistakes if you only copy numbers from your US 1099 into a German tax return.  In practice, many US expats in Germany use a local German tax advisor together with a US expat tax specialist like Taxbrella, so the German treatment of their US brokerage and retirement accounts lines up with the US return and avoids double taxation issues.