Foreign Broker: NBP D-1, W-8BEN, UPO, IBKR/DEGIRO

DISCLAIMER: Educational content, not tax advice. Laws PIT art. 30b, PL-USA double tax treaty. Consult advisor.

Introduction: Why IBKR can take 30% of dividend if you don’t click one form?

You have Coca-Cola shares in IBKR. Dividend 1000 USD. Without W-8BEN broker withholds 30% = 300 USD. With W-8BEN only 15% = 150 USD. Difference 150 USD = 600 PLN (~150 USD) per quarter. In year 2400 PLN loss for missing 5-minute form. Add to that wrong NBP rate and missing UPO and you have ready recipe for 5k loss yearly. This lesson is 60 minutes that returns 10x.

Table of contents

1. Why it matters for trader
2. NBP D-1 rate - only legal method
3. Conversion formula and NBP API
4. W-8BEN - how to lower WHT from 30% to 15%
5. UPO - your proof of PIT filing
6. How to settle IBKR, DEGIRO, eToro step by step
7. Table: broker -> report -> PIT -> rate
8. Market example: 50k USD turnover
9. Beginner mistakes
10. Exercises, checklist, next steps

1. Why does it matter for a trader?

Polish broker (XTB PL, mBank, Pekao) issues you PIT-8C and converts everything per NBP. Foreign (IBKR, DEGIRO, SAXO, Trading 212, eToro) does not issue PIT-8C and does not convert per NBP. You are payer and must:

• Download Activity / Annual Statement report
• Convert each transaction at NBP rate from previous day
• Fill PIT-38 (stocks) or PIT-36 (CFD/futures)
• Prove tax paid abroad (WHT)
• Keep UPO

`Effective_(foreign_tax) = WHT_(abroad) + (19%(PL) - WHT(creditable))

If WHT 15% in USA, then in PL you pay extra 4% to 19%. If WHT 30% (no W-8BEN) then in PL you won’t recover overpayment above 15% - you lose.

2. NBP D-1 Rate - sacred rule

Basis: art. 11a PIT, regulation on GDP. Revenue / cost in foreign currency converted at average NBP rate from last business day preceding day of obtaining revenue / incurring cost.

• Sale of stocks in USD 15.09.2025 -> take NBP rate from 12.09.2025 (because 14.09 Sunday)
• Dividend paid 10.06.2025 -> rate from 09.06.2025
• Commission 10.06.2025 -> rate from 09.06.2025

Where to get rate? NBP API: https://api.nbp.pl/api/exchangerates/rates/a/USD/2025-09-12/?format=json Table A, average rate.

For EUR, USD, GBP, CHF - separate tables. For NOK etc. also.

Formula:

Amount_(PLN = Amount_(USD × Rate_(NBP, table A, D-1

Income_(PLN = (Sale_(USD × NBP_(D-1^(sale) - (Purchase_(USD × NBP_(D-1^(purchase) - (Commissions_(USD × NBP_(D-1^(commission)

3. W-8BEN - magical form

What it is: IRS USA form confirming tax residency outside USA and right to lower withholding tax per PL-USA treaty.

• Without W-8BEN: WHT 30%
• With W-8BEN: WHT 15% on dividends, 0% on interest (some), 0% on capital gain (because PL)

How to fill in IBKR: IBKR -> Settings -> Tax Forms -> W-8BEN -> fill: name, surname, residency country PL, TIN = PESEL, treaty article 10 (dividends). Electronic signature. Valid 3 years.

DEGIRO, eToro - automatically ask.

Validity: 3 calendar years. If you don’t renew, it returns to 30%.

Savings example:

Dividend 10,000 USD yearly. Without W-8BEN: 3,000 USD withheld, you can deduct in PL max 15% = 1,500 USD, you lose 1,500 USD = 6,000 PLN. With W-8BEN: 1,500 USD withheld, you deduct 1,500 USD, pay extra 4% in PL = 400 USD, total effective 19%.

Saving_(W-8BEN = Dividend × (30% - 15%)

4. UPO - Official Receipt Confirmation

It’s xml/pdf from e-Tax Office confirming PIT filing. Without UPO you have no proof.

• File via e-Declarations / e-PIT.gov.pl
• Download UPO and save in /Taxes/UPO_2025.pdf
• UPO number = reference, valid in case of audit

What if filing via office? Ask for UPO. Many advisors don’t give - then you have no proof.

5. How to settle IBKR step by step (case 2025)

Step 1: IBKR -> Reports -> Tax -> Annual Statement + Activity Statement (Year), CSV Trades, Dividends, Withholding Tax.

Step 2: Separate:

• Stocks/ETF sale/purchase -> PIT-38
• Dividends -> PIT-38 dividend section + PIT/O
• CFD/futures -> PIT-36
• Interest -> PIT-38? Interest from IBKR cash is capital income (art.17) - PIT-38, but collected without PIT-8C, so you must yourself.

Step 3: Convert each line per NBP D-1. Use sheet with function:

=IMPORTDATA("https://api.nbp.pl/api/exchangerates/rates/a/USD/"&TEXT(A2-1,"yyyy-mm-dd")&"/?format=json") - need parsing.

Simpler: download NBP yearly table CSV from nbp.pl and VLOOKUP.

Step 4: Fill PIT-38:

• Section securities: revenue (sum sale PLN), cost (sum purchase PLN + commissions PLN)
• Section dividends: revenue, tax paid abroad, converted per NBP D-1 dividend day

Step 5: PIT/ZG or attachment - where to show foreign tax to deduct (proportional method).

Step 6: File, download UPO.

Table broker -> report -> PIT

6. Market example: Trader 50k USD

Jan, IBKR:

• Purchase: 100 NVDA @ 500 USD = 50k USD 2025-02-10, NBP D-1 3.95 = cost 197,500 PLN, commission 1 USD *3.95 =3.95 PLN
• Sale: 100 NVDA @ 700 USD =70k USD 2025-08-15, NBP D-1 3.90 = revenue 273,000 PLN, commission 1 USD *3.90=3.90 PLN
• Dividend: NVDA 50 USD 2025-05-15, NBP D-1 4.00 =200 PLN, WHT 15% =7.5 USD =30 PLN
• Stock income: 273k -197.5k -7.85 =75,492 PLN, tax 14,343 PLN
• Dividend: revenue 200 PLN, tax in PL 38 PLN (19%), paid abroad 30 PLN, extra to pay 8 PLN.
• Total PIT-38: 14,351 PLN (~3,587 USD).

Without NBP D-1, if counted per current rate 4.10, income would be 20k higher = 3.8k more tax.

7. Beginner mistakes

1. Rate from transaction day, not D-1 - most common, KAS checks.
2. No W-8BEN -> lose 15% irretrievably.
3. IBKR Futures in PIT-38 - most should go to PIT-36.
4. Dividends not shown because “XTB collected” - foreign broker is not PL payer, you must yourself.
5. UPO not downloaded - if PIT lost, you have no proof.
6. Mixing FIFO with NBP - first FIFO in currency, then conversion, not reverse.
7. eToro - thinking stocks are stocks - eToro sells you CFD with leverage despite “stocks”. Check agreement.

8. Practical exercises

Ex 1: Download from NBP USD rate of 2025-01-02 and from 2025-01-01 (holiday). See which API returns.

Ex 2: You have dividend 100 USD, WHT 15% =15 USD, NBP D-1 4.0. Calculate revenue PL, foreign tax PLN, tax to pay extra in PL.

Solution: Revenue 400 PLN, foreign 60 PLN, PL tax 76 PLN, extra 16 PLN.

Ex 3: Import IBKR Activity Statement CSV and add NBP D-1 column via VLOOKUP from NBP yearly table.

9. Checklist

• I have active W-8BEN (validity date checked)
• Downloaded Annual + Activity + Dividends from IBKR/DEGIRO
• Have NBP table USD/EUR 2025 (CSV)
• Converted each transaction NBP D-1 (not D)
• Separated PIT-38 vs PIT-36
• Calculated dividends + WHT + extra PL
• Have UPO from last year in folder
• Archived broker reports in /Foreign_Broker/2025/

10. Summary and Next Steps

Amount_{PLN} = Amount_{USD} × Rate_{NBP}(D-1)

• Foreign broker = you are payer.
• Always NBP D-1, always W-8BEN for USA.
• Always download UPO.
• IBKR stocks -> PIT-38, futures/forex -> PIT-36.

Next: Lesson 05 - Company abroad, CFC, substance, Estonia, Cyprus, UAE - when it makes sense and when you fall into CFC trap.