W-8BEN & US Dividend Withholding
What is W-8BEN?
W-8BEN is a US tax form that certifies you are a non-US tax resident. Filing it with your broker unlocks the reduced Poland–US treaty withholding rate (15%) on US dividends, instead of the default 30% backup withholding.
Why it matters for PIT-38
Poland credits foreign withholding only up to the treaty cap (15% for US). Any excess (e.g., 30% vs 15%) is not recoverable in Poland — you'd have to reclaim it from the IRS directly. kloPIT applies this cap automatically (see src/core/tax/treaty-rates.ts).
How kloPIT detects the issue
If a dividend row on the Dashboard shows a ⚠ warning, kloPIT detected withholding above the treaty cap (15% for US issuers). The excess is not creditable against your Polish tax.
Where to find it in IBKR
In IBKR Client Portal, open Settings → Account Settings → Tax Forms and submit/renew W-8BEN. Your broker handles the filing — you do not send the form to the IRS yourself.
W-8BEN expires every 3 years. A lapsed form is the most common cause of a sudden jump back to 30% withholding mid-year — re-submit before expiry.