A Polish private investor settling qualifying CFD income under article 30b generally uses PIT-38 and a nineteen-percent income-tax rate. Start by classifying the actual instruments and receipts, then reconcile revenue, eligible costs, prior losses and any foreign tax. Information supplied by a broker helps prepare the return, but its coverage and the actual contracting entity still need checking.

The colloquial name Belka tax combines distinct regimes. Article 30a covers specified interest and dividends, while article 30b covers specified disposals and realisation of financial-instrument rights. This guide assumes private CFD contracts classified as derivatives under article 30b paragraph 1, with no applicable business-activity exception. Ordinary currency exchange and prop-firm remuneration are not automatically the same income category. Determine the legal classification before applying the nineteen-percent rate.

The private derivative calculation concerns income: relevant revenue minus legally eligible costs. Reconcile both positive and negative contractual settlements, commissions and other entries; do not total only winning positions or count an embedded charge twice. The contractual realisation and cost-recognition rules determine which year each amount belongs to.

For derivative income, article 30b paragraph 2 point 3 refers to the cost rules in article 23 paragraph 1 point 38a. An expense’s usefulness or invoice alone does not establish deduction; assess the actual connection, recognition date and statutory conditions rather than assuming that every tool is eligible or that only commissions can ever qualify. Separately, qualifying article 30b income can enter the solidarity-levy base: four percent applies to the statutory excess over one million PLN, reported through DSF-1.

A Polish broker — does PIT-8C end the conversation?

For an entity subject to the Polish PIT-8C information obligation, the ordinary deadlines differ: electronic information goes to the tax office by the end of January, and the recipient’s copy by the end of February, in the following year, subject to the statutory time-limit rules. Check coverage and the actual contracting entity. PIT-8C is source information to reconcile with other relevant records, rather than a complete settlement in every case.

PIT-8C provides information; PIT-38 settles the year. Reconcile every relevant account and add legally required amounts absent from the prepared return. Eligible prepared PIT-38 returns in Twój e-PIT can be accepted automatically under the service rules, so manual submission is not the only route; automatic acceptance does not correct missing or misclassified amounts.

A foreign broker — you do the calculation, at the NBP rate

A foreign commercial brand does not by itself establish whether Polish PIT-8C reporting applies to its actual contracting entity. If no information form covers the relevant income, obtain complete statements and calculate the Polish settlement from the records. Absence of PIT-8C does not remove a Polish resident’s applicable income-reporting obligation.

  • Download complete transaction and cash-adjustment records for the relevant tax year. Check the report offered by the actual contracting entity rather than relying on a particular report name.
  • Under article 11a, convert foreign-currency revenue using the NBP average rate from the last business day before revenue is obtained, and eligible costs using the last business day before the cost is incurred. Those recognition dates can differ. For a Monday event, Friday applies only if it was the relevant preceding business day.
  • Reconcile revenue and eligible costs within each applicable income category. Keep interest, dividends and virtual-currency transactions separate from the qualifying private derivative settlement; include an eligible commission once.
  • Report the properly classified PLN amounts in the relevant PIT-38 sections. Assess any PIT/ZG attachment from the actual foreign-source income and applicable treaty; the broker’s address alone is not a source-country test. Check the conditions and limits before claiming a foreign-tax credit.

Use the statutory NBP rate and recognition date separately for revenue and costs, rather than the bank’s conversion rate or an annual average. Also reconcile income for which no PIT-8C was supplied. CRS exchanges concern reportable financial-account information under applicable rules and activated jurisdiction relationships; they do not guarantee that a named broker’s balance is always sent to Poland. Retain the records needed for your settlement in the taxes chapter workflow.

Equal dollar amounts can leave a positive PLN result

Our invented model correctly recognises USD 1,000 revenue and USD 1,000 eligible tax costs in one year, on different applicable dates. Their assumed conversion rates are PLN 4.20 and 4.00 per USD respectively. The dollar balance alone does not determine the Polish tax result.

Scroll sideways to see the full diagram

Zero in dollars, a positive difference in zlotyHypothetical USD 1,000 revenue at an applicable invented rate of PLN 4.20 gives PLN 4,200. USD 1,000 costs at a different applicable invented rate of PLN 4.00 give PLN 4,000. The USD difference is zero, but the converted difference is PLN 200. These are not actual NBP quotations.Convert each event, not the USD balanceRevenue: USD 1,000 × 4.20PLN 4,200Costs: USD 1,000 × 4.00PLN 4,000USD: 1,000 − 1,000 = 0PLN: 4,200 − 4,000 = 200
Each bar shows the converted PLN amount on the same scale.

4,200 − 4,000 = PLN 200 difference. First calculating 1,000 − 1,000 USD and then converting zero at one rate loses the separate-conversion effect. Record each tax recognition date and its applicable rate date. These are related but distinct findings: a bank-transfer date does not automatically determine tax recognition.

Assumptions: Poland, a hypothetical 2026 year. Both events belong to that year: correctly recognised Article 30b revenue and an eligible cost. Rates 4.20 and 4.00 are invented and represent two different applicable rates from the last working day before each relevant date. They are not actual NBP readings. No other events or deductions. Official source: The PIT Act, Article 11a(1)–(2).

Swap and interest — capital income too?

Separate private derivative settlements from interest on the account balance and dividends, which can belong to different PIT provisions. For financing or swap entries, check the contract, recognition dates and whether the report already includes the amount in its result; a broker’s presentation does not alone settle legal classification. Include an eligible amount once. What is a forex swap explains the trading mechanics.

Prior-year loss — five years and two routes

If you closed a year in the red, you have five subsequent years to deduct that loss from capital income — but with a meaningful limit. Article 9 paragraph 3 of the PIT Act offers a choice of two routes. The classic one: in any single year you may deduct at most 50 percent of the loss from a given originating year, across the five consecutive years. A 40,000 PLN loss from 2023 therefore entitles you in 2026 to a deduction of no more than 20,000 PLN, with the remainder settled in any of the remaining years up to 2028 inclusive, under the same cap. The alternative, available for losses arising from 2019 onwards, is a one-off deduction in one of those five years, up to 5 million PLN. On a retail investor's account that simply means the option to settle the whole loss at once, provided there is enough income to set it against.

A qualifying private derivative loss can reduce income in the relevant article 30b settlement under the statutory source and time restrictions. It does not reduce salary or ordinary business income, and virtual-currency costs and results have their separate rules even though they appear on PIT-38. Track each original loss year and its five following deduction years. If a loss was omitted, assess a valid correction of its original year; correction does not restart that deduction window. See Forex loss tax.

A hypothetical tax year — from statements to wire transfer

Illustrative example — trader with XTB and Interactive Brokers, tax year 2025
XTB account (PLN)Realised income per PIT-8C: 50,000 PLN
IBKR account (USD)Correctly reconciled revenue and eligible costs converted separately using their applicable recognition dates: PLN 20,000 income
Loss carried from 2023Original qualifying 2023 loss PLN 40,000, still entirely unused: the classic route deducts PLN 20,000 in this model; window 2024–2028
Taxable base50,000 plus 20,000 minus 20,000, which equals 50,000 PLN; on the one-off route it would be 30,000 PLN
Tax dueOn 50,000 PLN the tax is 19 percent and amounts to 9,500 PLN payable
DeadlineFile PIT-38 and wire the payment to the tax office by 30 April 2026

This model assumes private income within the same eligible settlement, the original loss still unused and no other adjustments. The one-off PLN 40,000 deduction would leave a PLN 30,000 base and PLN 5,700 ordinary PIT, compared with PLN 9,500 under the illustrated classic route. Deduction timing also changes the loss left for later eligible years; no route is automatically best.

What most often goes wrong

Keep four checks separate. Reconcile all relevant accounts; classify receipts before combining them; track each original loss and its window; and retain source records for the applicable procedural period. Consider an invented Polish private-investment year with a PLN 100 CFD loss, PLN 300 ordinary domestic deposit interest and PLN 500 correctly established virtual-currency income. Assume no exemptions, foreign tax or other adjustments. The bank withholds PLN 57 on interest; the virtual-currency calculation gives PLN 95. Total burden is PLN 152, including the bank’s already withheld amount. Combining −100 + 300 + 500 and taxing PLN 700 would give PLN 133, understating the model by PLN 19. Sharing a nineteen-percent rate or PIT-38 form does not make the bases interchangeable.

What to do tomorrow

  1. Download complete statements for the tax year being settled. Label files with that year and the contracting entity, including transaction records, cash adjustments and the documents used to establish eligible costs.
  2. Check PIT-8C broker forex and the actual contracting entity’s information obligation. Request missing documents or clarification of their coverage rather than assuming that every domestic brand owes a form for every account.
  3. Identify the relevant revenue and eligible-cost recognition dates separately, then assign each foreign-currency amount the NBP average rate from the last preceding business day. Keep the date, currency, rate, original amount and PLN calculation in the reconciliation sheet.
  4. If you carry unused losses from prior years, open the article on losses and decide which of the two routes in article 9 paragraph 3 you are taking this year — 50 percent of the loss from each originating year separately, or a one-off deduction up to 5 million PLN. Work out both figures on paper before you enter anything on PIT-38; the choice determines how much loss is left for the following years.
  5. Check the applicable filing and payment deadlines and the completed return, including any automatic acceptance in Twój e-PIT. For an automatically accepted return with tax due, check the official notification and its payment rules; the service describes payment within seven days of receiving that notice. A manual filing and any arrears require their own assessment. Save the return and filing confirmation, and check other levies beyond PIT-38.