Czech Republic Personal Income Tax Return — Separate Tax Base Computation Annex (Příloha č. 4 k Přiznání k dani z příjmů fyzických osob)

This file is the source-review record for this document version, per the manual-source-review-v1 practice.

Current claim

• status: draft
• verification.method: manual-source-review-v1
• verification.lastVerifiedAt: 2026-07-09
• maturity.level: structural-reference

Why this cycle picked up Příloha č. 4

This is the recurring "GovSchema Standard Research" cycle (GOV-1998). The already-published base return, cz/mf/priznani-k-dani-z-prijmu-fyzickych-osob (GOV-1826), explicitly named and deferred this exact document in its own description:

> "It deliberately does NOT model: Příloha č. 1 (self-employment income, §7 > zákona), Příloha č. 2 (rental and other income, §9/§10 zákona), Příloha č. 3 > (foreign-source income tax computation, §38f zákona), Příloha č. 4 > (separate tax base, §16a zákona), ..."

The already-published Příloha č. 3 (cz/mf/priloha-3-vypocet-dane-z-prijmu-ze-zdroju-v-zahranici, GOV-1991) independently flagged this exact document as the sole remaining open backlog candidate in its own description/verification.notes and CATALOG.md's own Executive Summary update ("Příloha č. 4 (separate tax base, §16a zákona) is now the sole remaining open backlog candidate in this companion-schedule sequence"). This document closes that gap: a companion schedule to the already-published base return, the same pattern this registry has used eleven times for Canton Zürich's ch/zh/sta/hilfsblatt-*/companion- schedule family and three times already for this same base return (Přílohy č. 1-3). It does not open a new vertical or jurisdiction — the Czech Republic remains at 4 of 6 verticals (Business Formation, DMV, Visa, Taxes). This closes the base return's own companion-schedule backlog (Přílohy č. 1-4) entirely.

Edition discovery

financnisprava.gov.cz's own "Daňové tiskopisy" listing page, https://financnisprava.gov.cz/cs/dane/danove-tiskopisy, was fetched directly (HTTP 200, no login/CAPTCHA/WAF gate — the same page every prior CZ cycle has used) and searched for its own Příloha č. 4 entry. This confirms:

• Two editions of 25 5405/P4 are currently listed: vzor č. 12 (5405-P4_12.pdf) and vzor č. 13 (5405-P4_13.pdf). Following the same convention established by Přílohy č. 1-3 (each of which also listed two editions on this page, e.g. Příloha č. 3's vzor č. 21 alongside its current vzor č. 22), the higher-numbered edition, vzor č. 13, is the current one — confirmed directly by its own printed cover text, "za zdaňovací období 2026 – 25 5405 MFin 5405 vzor č. 30" (the same base-return edition Přílohy č. 1-3 all cite as current).
• An English-language variant, 5405-P4a_12.pdf, is also listed, one edition behind the current Czech vzor č. 13 — the same one-edition lag Příloha č. 3's own 5405-P3a_21.pdf (vs. current vzor č. 22) showed.

This document's own source.url cites https://financnisprava.gov.cz/assets/tiskopisy/5405-P4_13.pdf, fetched fresh this cycle.

Sources examined

• Document (id, version): cz/mf/priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane / 1.0.0
• Spec version: GovSchema 0.3.0
• Authority: Ministerstvo financí (MFin), operated by Finanční správa České republiky — identical to the base return's own authority and to Přílohy č. 1-3's own authority.
• Primary source: https://financnisprava.gov.cz/assets/tiskopisy/5405-P4_13.pdf — "25 5405/P4 MFin 5405/P4 - vzor č. 13," fetched directly this cycle (HTTP 200, 153,862 bytes, %PDF, 2 pages per its own page count). A raw byte-level scan for the literal strings /AcroForm and /Widget returned zero matches for both — a flat print/reference facsimile PDF, the same shape as the base return and Přílohy č. 1-3.
• This annex's own embedded instructions. Page 2 of this same 2-page PDF prints a self-contained "POKYNY K PŘÍLOZE č. 4" section restating every numbered line's purpose and statutory basis directly — confirmed by direct pdfjs-dist text extraction of both pages in one pass. This is this document's sole and sufficient explanatory source; no second PDF was needed to explain any field on this annex, the same pattern as Přílohy č. 1-3.
• Extraction method. pdfjs-dist v3 (legacy/build/pdf.js, loaded via a scratch npm install since the repo's own tools/ workspace does not vendor it) getTextContent() for body text and getAnnotations() filtered to subtype === 'Widget' for the AcroForm-field check, the same reviewer-confirmed technique used across this registry's PDF-based schemas. Both pages extracted cleanly with no garbling and zero Widget annotations.
• Retrieved / reviewed: 2026-07-09.
• Reviewer: GovSchema Engineering (Standards Engineer — initial authoring source review).

Line-by-line classification (ř. 401-414)

• ř. 401 — raw taxpayer-entered amount, no formula → foreignPartnershipIncomeSection7 (field).
• ř. 401a — raw taxpayer-entered amount; its own instructions describe a netting the filer applies before entry (loan/credit interest, net of interest paid to fund that loan/credit), but no formula referencing another numbered line → foreignCapitalIncomeSection8 (field).
• ř. 402 — raw taxpayer-entered amount, no formula → foreignOtherIncomeSection10 (field).
• ř. 403 — raw taxpayer-entered amount (expenses), no formula → expensesForPrizeIncomeSection10 (field).
• ř. 404 — raw taxpayer-entered amount, no formula → foreignSettlementLiquidationIncome (field).
• ř. 405 — raw taxpayer-entered amount (expenses), no formula → expensesForSettlementLiquidationIncome (field).
• ř. 406 ("Úhrn dílčího samostatného základu daně podle § 7 a dílčího samostatného základu daně podle § 8 zákona (ř. 401 + ř. 401a po snížení podle § 8 odst. 9 zákona)") — see the dedicated scope decision below: not treated as pure arithmetic → section7Section8CombinedBase (field).
• ř. 407 ("Dílčí samostatný základ daně z příjmů podle § 10 odst. 1 písm. h) bod 1, ch) a o) zákona (ř. 402 – ř. 403)") — formula references only ř. 402 and ř. 403, both already-modelled fields on this same annex, with no external operand and no "nebo" branching → excluded as pure arithmetic (foreignOtherIncomeSection10 − expensesForPrizeIncomeSection10).
• ř. 408 ("Dílčí samostatný základ daně z příjmů podle § 10 odst. 1 písm. f) a písm. g) zákona (ř. 404 – ř. 405)") — formula references only ř. 404 and ř. 405, both already-modelled fields → excluded as pure arithmetic (foreignSettlementLiquidationIncome − expensesForSettlementLiquidationIncome).
• ř. 409 ("Součet dílčích základů daně (ř. 406 + ř. 407 + ř. 408) zaokrouhlený na celá sta Kč dolů") — formula references ř. 406 (an already-modelled field), ř. 407, and ř. 408 (both excluded above but purely derivable from other already-modelled fields on this same annex) — no operand outside this document → excluded as pure arithmetic (section7Section8CombinedBase + (foreignOtherIncomeSection10 − expensesForPrizeIncomeSection10) + (foreignSettlementLiquidationIncome − expensesForSettlementLiquidationIncome), rounded down to whole hundreds of CZK).
• ř. 410 ("Daň se sazbou 15 % ze součtu dílčích základů daně (ř. 409) - uveďte vypočtenou daňovou povinnost") — formula references only ř. 409 (excluded above, itself purely derivable), multiplied by the fixed 15% statutory rate — no external operand, no branching → excluded as pure arithmetic.
• ř. 411 — raw taxpayer-selected subset, no unconditional formula (see the dedicated scope decision below) → incomeEligibleForForeignTaxCredit (field).
• ř. 412 — raw taxpayer-entered amount, no formula → foreignTaxPaidOnCreditEligibleIncome (field).
• ř. 413 ("Daň uznaná k zápočtu (ř. 412 maximálně do výše 15 % z částky uvedené na ř. 411)") — min(foreignTaxPaidOnCreditEligibleIncome, 0.15 × incomeEligibleForForeignTaxCredit), both already-modelled fields on this same annex, no external operand → excluded as pure arithmetic.
• ř. 414 ("Daň ze samostatného základu daně podle § 16a zákona (ř. 410 – ř. 413)") — both ř. 410 and ř. 413 are excluded above but purely derivable from other already-modelled fields on this same annex, with no external operand and no "nebo" branching → excluded as pure arithmetic. Its own instructions direct the filer to carry this result, rounded up to whole CZK, to the base return's own ř. 74a, 5. oddíl — a cross-document transfer, not modelled here (consistent with every other CZ annex's own treatment of its own transfer-out line).

Scope decision: ř. 406 is modelled as its own field, not pure arithmetic

Every other pure-sum/difference line on this annex (ř. 407, 408, 409, 413, 414) is excluded because it is fully and unconditionally derivable from other already-modelled fields on this same document, with no operand this registry does not capture anywhere. Ř. 406 is different: its own printed formula is "ř. 401 + ř. 401a po snížení podle § 8 odst. 9 zákona" (after reduction per §8 odst. 9 zákona) — a reduction applied at this line, distinct from the loan/credit-interest netting foreignCapitalIncomeSection8's (ř. 401a's) own instructions already describe for entering that line. No field on this annex captures the §8 odst. 9 expense amount itself; it is never a separately printed line anywhere on this 2-page document. Because this line's own formula depends on an adjustment this registry has no field to hold, ř. 401 + ř. 401a alone cannot be guaranteed to equal ř. 406 in every case — the same reasoning Příloha č. 3 applied to its own ř. 314 (excluded from pure-arithmetic treatment because one of its operands, an odčitatelné-položky amount, is never captured as its own field). ř. 406 is therefore modelled as its own field, section7Section8CombinedBase, one the filer computes off this schema and enters directly — the more conservative reading, and the one this document's own field description discloses. A future review should re-examine whether §8 odst. 9 zákona's own expense categories are common enough among likely filers of this annex to warrant modelling as a dedicated field of their own.

Scope decision: ř. 411 is modelled as its own field, not derived from ř. 406-408

Ř. 411's own label ("Úhrn příjmů, u nichž se uplatní zápočet – z příjmů uvedených na ř. 406, ř. 407 a ř. 408") reads, at first glance, like an aggregate of ř. 406 + 407 + 408. It is not: it is the taxpayer-selected subset of that combined income for which the ordinary foreign-tax-credit method is actually being claimed. A taxpayer may hold foreign-source income within this annex's scope for which no foreign tax was withheld at all (so no credit is claimed for that portion), meaning ř. 411 can be strictly less than ř. 406 + ř. 407 + ř. 408. This annex's own instructions confirm the plain-language framing ("uveďte úhrn příjmů, tj. dílčích samostatných základů daně ... u nichž se uplatní zápočet" — "state the sum of the partial separate tax bases ... for which the credit is applied"), not a printed arithmetic formula with a "(ř. X + ř. Y)" notation the way every genuinely pure-arithmetic line on this annex carries. ř. 411 is therefore modelled as its own field, incomeEligibleForForeignTaxCredit.

Field-by-field source mapping

• Strana (1), header ("Rodné číslo:") → birthNumber.
• 1. Výpočet daně ze samostatného základu daně podle § 16a zákona (ř. 401-414) → foreignPartnershipIncomeSection7 (401), foreignCapitalIncomeSection8 (401a), foreignOtherIncomeSection10 (402), expensesForPrizeIncomeSection10 (403), foreignSettlementLiquidationIncome (404), expensesForSettlementLiquidationIncome (405), section7Section8CombinedBase (406), incomeEligibleForForeignTaxCredit (411), foreignTaxPaidOnCreditEligibleIncome (412). Ř. 407, 408, 409, 410, 413, and 414 pure arithmetic — see classification above.

Mock-data test run

This annex has no discriminator field (a filer reports whichever of the three income categories applies), and no live filing wizard exists for this PDF-based annex — the same limitation the base return and Přílohy č. 1-3 all disclose. One worked, internally-consistent scenario was constructed instead, and every excluded line re-derived by hand.

Scenario — "Hana Dvořáková," German dividend income (§8) and a UK lottery prize (§10)

birthNumber = "8002151234".

• foreignPartnershipIncomeSection7 = 0 — no §7 odst. 14 partnership income this scenario.
• foreignCapitalIncomeSection8 = 300000 — dividend income from a German public company, converted to CZK, electing the flat 15% separate-tax-base rate under §16a zákona instead of folding it into the base return's own progressive computation (so it is not also entered on the base return's own capitalIncomeTaxBase, ř. 38).
• foreignOtherIncomeSection10 = 150000 — a UK National Lottery prize, converted to CZK.
• expensesForPrizeIncomeSection10 = 0 — no remuneration-for-work-use component in a lottery prize (unlike, e.g., a public-competition prize for an entered creative work), so no offsetting expense.
• foreignSettlementLiquidationIncome = 0, expensesForSettlementLiquidationIncome = 0 — no §10 odst. 1 písm. f)/g) income this scenario.
• section7Section8CombinedBase = 300000 — ř. 401 (0) + ř. 401a (300,000), with no §8 odst. 9 zákona reduction applicable this scenario (the dividend income is not within §8 odst. 1 písm. e)/f) zákona), so this field equals the unadjusted sum. Verified: consistent with the formula given no applicable §8/9 reduction this scenario.
• ř. 407 (derived, not stored) = 150,000 − 0 = 150,000.
• ř. 408 (derived, not stored) = 0 − 0 = 0.
• ř. 409 (derived, not stored) = round-down-to-hundreds(300,000 + 150,000 + 0) = 450,000 (already a round hundred).
• ř. 410 (derived, not stored) = 450,000 × 15 / 100 = 67,500.
• incomeEligibleForForeignTaxCredit = 150000 — only the UK lottery prize had foreign tax withheld this scenario (the German dividend's own withholding was separately reclaimed under the CZ-DE treaty and is not credited here, by this taxpayer's choice); the credit-eligible subset is therefore strictly less than ř. 406 + ř. 407 + ř. 408 (450,000), confirming ř. 411 is not a pure aggregate — see the scope decision above.
• foreignTaxPaidOnCreditEligibleIncome = 30000 — 20% UK withholding on the lottery prize, evidenced by HMRC's own confirmation of payment.
• ř. 413 (derived, not stored) = min(30,000, 0.15 × 150,000) = min(30,000, 22,500) = 22,500 (the credit is capped; 7,500 Kč of UK tax is not creditable this scenario).
• ř. 414 (derived, not stored) = 67,500 − 22,500 = 45,000, rounded up to whole CZK (already whole) — transferred by the filer to the base return's own ř. 74a.
• Result: OK. Every excluded line (ř. 407-410, 413, 414) re-derives correctly by hand from this scenario's own field values, and the scenario specifically exercises the case the scope decision above flags — incomeEligibleForForeignTaxCredit strictly less than the sum of ř. 406-408 — confirming that field cannot be safely treated as derived.

Negative control — §7 partnership income only, no credit claimed

A taxpayer with only foreignPartnershipIncomeSection7 populated (say, 80,000 Kč) and every other field left blank/zero validates structurally against this schema (every field is required: false, no requiredWhen), since ř. 409 (450,000 → n/a here, would instead be 80,000 rounded down to hundreds) and ř. 410 (12,000) still derive correctly from that single field, and incomeEligibleForForeignTaxCredit/ foreignTaxPaidOnCreditEligibleIncome are correctly left unset when no foreign tax was withheld on this income at all. This confirms the schema does not force a filer using only one of the three income categories to populate fields belonging to the others, nor to claim a credit that does not apply.

Both registry validators were run against the schema document itself and pass:

``` $ node tools/validate.mjs registry/cz/mf/priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane/1.0.0/schema.json ok registry/cz/mf/priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane/1.0.0/schema.json

1/1 document(s) passed.

$ node tools/validate-ajv.mjs registry/cz/mf/priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane/1.0.0/schema.json ok registry/cz/mf/priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane/1.0.0/schema.json [v0.3]

1/1 document(s) validated against the meta-schema (ajv 2020-12). ```

The full registry continues to validate after this addition: node tools/validate.mjs and node tools/validate-ajv.mjs (run with no arguments, scoping the whole registry) both report 311/311 document(s) passed — 310 pre-existing schema documents plus this one (the mapping.json companions are unaffected: 3/3 pass both before and after).

What is NOT modelled (out of scope), and why

• ř. 407, ř. 408, ř. 409, ř. 410, ř. 413, ř. 414 — each a pure arithmetic function of other fields already captured on this same annex; see the line-by-line classification above.
• The §8 odst. 9 zákona expense reduction applied at ř. 406 — not its own field; the annex prints no dedicated line for it, and it is subsumed into the filer-entered section7Section8CombinedBase value — see the dedicated scope decision above.
• The cross-document transfer to the base return (ř. 414's result to ř. 74a) — the base return's own schema does not model that destination line, per its own documented exclusion of every downstream computed line; consistent with every other CZ annex's own treatment of its own transfer-out line.
• The mutual-exclusivity relationship with the base return's own capitalIncomeTaxBase (ř. 38) — described in foreignCapitalIncomeSection8's own field description and this document's top-level description, but not enforced as a crossFieldValidation rule, since the two are fields on two separate documents this spec version has no cross-document constraint mechanism for.
• A separate signature/filing-date block — this annex has none of its own; it is filed as a physical/electronic attachment to the base return, which alone carries the DAP's one signature. Confirmed by searching this annex's own extracted text for "podpis"/"datum vyhotovení" — zero matches across both pages, the same finding Přílohy č. 1-3's own cycles made.

Judgment calls

1. Ř. 407, 408, 409, 410, 413, 414 are excluded as pure arithmetic, each derivable entirely from other fields already modelled on this same annex with no external/base-return operand and no "nebo" branching — see the line-by-line classification above for the full reasoning per line.
2. Ř. 406 is modelled as its own field despite carrying a printed "(ř. 401 + ř. 401a ...)" formula, because that same formula also names a further §8 odst. 9 zákona reduction this registry has no field for — the more conservative reading; see the dedicated scope decision above.
3. Ř. 411 is modelled as its own field, not derived from ř. 406-408, because it is the taxpayer's own selected credit-eligible subset of that combined income, not a printed sum of those lines — see the dedicated scope decision above.
4. birthNumber is modelled as optional, mirroring the base return's and Přílohy č. 1-3's own birthNumber field and its own disclosed reasoning.
5. Amounts are modelled as plain number fields in whole CZK, per this annex's own repeated instruction ("Částky uveďte v celých Kč") for entered amounts, the same convention as the base return and Přílohy č. 1-3.
6. No crossFieldValidation rules were added — every field on this annex is independently optional (a filer may hold income under any combination of the three source categories, or none), the same reasoning the base return's and Přílohy č. 1-3's own VERIFICATION.md give for omitting crossFieldValidation.
7. No live submission was attempted — filing a real Czech personal income tax return annex is a real legal act with a real national tax authority, not a safe or reversible action to simulate against a live government process, consistent with this registry's standing discipline.

Access notes

No access blocks: financnisprava.gov.cz was reachable directly from this environment with plain curl for the listing page and this annex's own current PDF edition — no TCP-level reset, WAF, or CAPTCHA gate encountered, consistent with the base return's and Přílohy č. 1-3's own findings for the same domain.

tools/verify-sources.mjs was run scoped to this document's own registry directory and confirms every cited URL is live and independently reachable:

``` $ node tools/verify-sources.mjs registry/cz/mf/priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane verify-sources: checking 1 schema version directory...

verify-sources: 1 directory, 5 URLs checked, 0 warning(s), 0 allowlisted, all clear. ```

Scope and jurisdiction notes

• This is a companion-schedule addition to an already-published Taxes-vertical document (cz/mf/priznani-k-dani-z-prijmu-fyzickych-osob), not a new vertical or jurisdiction; the Czech Republic remains at 4 of 6 verticals.
• id uses the same cz/mf authority-directory segment as the base return and Přílohy č. 1-3 (Ministerstvo financí), with a slug, priloha-4-vypocet-dane-ze-samostatneho-zakladu-dane, ASCII-folded from the annex's own printed subtitle ("výpočet daně ze samostatného základu daně"), consistent with this registry's existing CZ naming convention of using the form's own official title/subtitle as the slug.
• Conditional requiredness (requiredWhen) is not used in this document — like Přílohy č. 2-3, this annex has no discriminator field gating groups of other fields; every field is independently, unconditionally optional.
• No edition member is used, consistent with the base return's and Přílohy č. 1-3's own treatment (this annex, like all four, is hosted at a version-independent URL that is simply replaced each tax year, not a registry-modelled edition axis).
• This closes the base return's own companion-schedule backlog (Přílohy č. 1-4) entirely; the Czech Republic's own remaining open verticals are Passport and National ID, both confirmed dead ends (in-person-only, no citizen-facing application form) per GOV-1819/GOV-1826's own findings.

Re-verification

Per the practice's cadence, nextReviewBy is set to 2027-01-09 (6 months), the same cadence as the base return and Přílohy č. 1-3. Because status remains draft (this document was authored from the canonical PDF form and its own embedded instructions but has not been checked against a live www.mojedane.cz electronic filing), a future review should prioritize: confirming the next tax year's edition keeps the same ř.-number scheme, re-confirming the §8 odst. 9 zákona reduction and the credit-cap floor described above have not changed, and re-examining whether §8 odst. 9 zákona's own expense categories are common enough to warrant their own dedicated field (see the ř. 406 scope decision above).