Band savings and dividends above property income

changelog.d/2351.fixed.md

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+Band savings and dividend income above property income, which is non-savings income (ITA 2007 ss. 16, 16A), including in the income the annual allowance charge's marginal rate is read from.

policyengine_uk/tests/policy/baseline/gov/hmrc/income_tax/property_income_band_base.yaml

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+# Savings and dividend income are the highest part of total income (ITA 2007
+# s. 16), so property income, like pay, fills the bands below them. 2026-27,
+# single adult: personal allowance £12,570, basic rate limit £37,700, savings
+# allowance £500 for a higher-rate taxpayer, dividend allowance £500 at
+# 10.75% / 35.75%.
+
+- name: Case 1, dividends sit above property income.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        property_income: 40_000
+        dividend_income: 20_000
+    households:
+      household:
+        members: [person]
+        country: ENGLAND
+  output:
+    # Non-savings taxable income 40,000 - 12,570 = 27,430. The £500 dividend
+    # allowance and 9,770 fill the basic-rate band (9,770 x 10.75% =
+    # 1,050.275); 9,730 is at 35.75% (3,478.475). Total 4,528.75, as for pay.
+    non_savings_taxable_income: 27_430
+    dividend_income_tax: 4_528.75
+    income_tax: 5_486 + 4_528.75
+
+- name: Case 2, savings sit above property income.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        property_income: 40_000
+        savings_interest_income: 20_000
+    households:
+      household:
+        members: [person]
+        country: ENGLAND
+  output:
+    # £500 savings allowance, then 9,770 at 20% (1,954) to the basic rate
+    # limit and 9,730 at 40% (3,892).
+    savings_income_tax: 5_846
+
+- name: Case 3, pay and property income together form the band base.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        employment_income: 10_000
+        property_income: 30_000
+        dividend_income: 20_000
+    households:
+      household:
+        members: [person]
+        country: ENGLAND
+  output:
+    # The allowance covers the pay first: 0 earned and 27,430 property
+    # income taxable, so dividends sit on 27,430 as in Case 1.
+    taxable_property_income_after_allowances: 27_430
+    non_savings_taxable_income: 27_430
+    dividend_income_tax: 4_528.75
+
+- name: Case 4, a Scottish taxpayer's dividends use UK bands above the property income.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        property_income: 40_000
+        dividend_income: 20_000
+    households:
+      household:
+        members: [person]
+        country: SCOTLAND
+  output:
+    dividend_income_tax: 4_528.75
+
+- name: Case 5, from 2027-28 property income has its own rates but still sits below dividends.
+  period: 2027
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        property_income: 40_000
+        dividend_income: 20_000
+    households:
+      household:
+        members: [person]
+        country: ENGLAND
+  output:
+    # Property income at the 22% property basic rate: 27,430 x 22% = 6,034.60.
+    property_income_tax: 6_034.60
+    dividend_income_tax: 4_528.75
+
+- name: Case 6, the annual allowance charge reads the rate on property income too.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        employment_income: 10_000
+        property_income: 60_000
+        employee_pension_contributions: 70_000
+    households:
+      household:
+        members: [person]
+        country: ENGLAND
+  output:
+    # Relief is limited to the £10,000 of pay, so taxable income is
+    # 70,000 - 12,570 - 10,000 = 47,430, in the higher-rate band; the
+    # £10,000 over the £60,000 annual allowance is charged at 40%.
+    taxed_income: 47_430
+    personal_pension_contributions_tax: 4_000
+
+- name: Case 7, Marriage Allowance still comes off the band base (pinned; #1947).
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person:
+        age: 45
+        employment_income: 20_000
+        property_income: 10_000
+        marriage_allowance: 1_260
+    households:
+      household:
+        members: [person]
+        country: ENGLAND
+  output:
+    # earned_taxable_income subtracts Marriage Allowance, which the law gives
+    # as a tax reduction (ITA 2007 s. 55B), so the base is 30,000 - 12,570 -
+    # 1,260 = 16,170 rather than 17,430. Pinned here until #1947 is fixed.
+    non_savings_taxable_income: 16_170
+    non_savings_income_after_allowances: 17_430

policyengine_uk/tests/policy/integration/income.yaml

@@ -100,8 +100,13 @@
       members: [person1, person2]
   output:
     property_income_tax: [17_792, 6_776.20]
-    savings_income_tax: [0, 0]
-    income_tax: [17_792, 6_776.20]
+    # Savings sit above the property income (ITA 2007 s. 16). Person 1:
+    # 75,900 - 12,570 = 63,330 of non-savings taxable income, so a higher-
+    # rate taxpayer with a £500 savings allowance and no starting rate:
+    # (2,900 - 500) x 40% = 960. Person 2: 46,451 - 12,570 = 33,881, a
+    # basic-rate taxpayer with £1,000: (1,525 - 1,000) x 20% = 105.
+    savings_income_tax: [960, 105]
+    income_tax: [18_752, 6_881.20]
 
 - name: Household net income can be negative
   period: 2020

policyengine_uk/tests/test_property_income_band_base_properties.py

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+"""Savings and dividends sit above all non-savings income (ITA 2007 s. 16).
+
+Property income is non-savings income, so it fills the bands before savings
+and dividends, as pay does.
+
+Invariants, for single adults in 2026 with pay, property income, savings
+interest and dividends drawn freely:
+
+1. Differential: replacing property income with pay equal to its taxable
+   amount leaves savings and dividend tax unchanged, in England and in
+   Scotland. (The taxable amount, because the £1,000 property allowance can
+   relieve small property income in full.)
+2. Accounting: with no Marriage Allowance, non_savings_taxable_income equals
+   adjusted net income less savings, dividends and allowances, floored at nil
+   (earned_taxable_income also subtracts Marriage Allowance; #1947).
+3. Monotonic: more property income never lowers savings or dividend tax.
+   (Main passes this too; the differential and the higher-rate check below
+   are what catch the bug.)
+"""
+
+import numpy as np
+from hypothesis import HealthCheck, given, settings
+from hypothesis import strategies as st
+
+from policyengine_uk import Simulation
+
+YEAR = 2026
+PEOPLE = 10
+amount = st.integers(min_value=0, max_value=200_000)
+rows_strategy = st.lists(
+    st.tuples(amount, amount, st.integers(0, 60_000), st.integers(0, 60_000)),
+    min_size=PEOPLE,
+    max_size=PEOPLE,
+)
+VARIABLES = [
+    "taxable_property_income",
+    "savings_income_tax",
+    "dividend_income_tax",
+    "non_savings_taxable_income",
+    "adjusted_net_income",
+    "taxable_savings_interest_income",
+    "taxable_dividend_income",
+    "allowances",
+]
+
+
+def _calculate(rows, country):
+    """rows: (pay, property, savings, dividends), one single adult each."""
+    people, benunits, households = {}, {}, {}
+    for i, (pay, prop, savings, dividends) in enumerate(rows):
+        name = f"p{i}"
+        people[name] = {
+            "age": {YEAR: 45},
+            "employment_income": {YEAR: pay},
+            "property_income": {YEAR: prop},
+            "savings_interest_income": {YEAR: savings},
+            "dividend_income": {YEAR: dividends},
+        }
+        benunits[f"b{i}"] = {"members": [name]}
+        households[f"h{i}"] = {"members": [name], "country": {YEAR: country}}
+    simulation = Simulation(
+        situation={"people": people, "benunits": benunits, "households": households}
+    )
+    return {v: np.asarray(simulation.calculate(v, YEAR)) for v in VARIABLES}
+
+
+SETTINGS = settings(
+    max_examples=8,
+    deadline=None,
+    suppress_health_check=[HealthCheck.too_slow],
+)
+
+
+@SETTINGS
+@given(rows=rows_strategy, country=st.sampled_from(["ENGLAND", "SCOTLAND"]))
+def test_moving_income_between_pay_and_property_leaves_savings_and_dividend_tax(
+    rows, country
+):
+    as_property = _calculate(rows, country)
+    taxable_property = as_property["taxable_property_income"]
+    as_pay = _calculate(
+        [
+            (pay + float(taxable), 0, s, d)
+            for (pay, _, s, d), taxable in zip(rows, taxable_property)
+        ],
+        country,
+    )
+    for name in [
+        "savings_income_tax",
+        "dividend_income_tax",
+        "non_savings_taxable_income",
+    ]:
+        np.testing.assert_allclose(as_property[name], as_pay[name], atol=0.01)
+
+
+@SETTINGS
+@given(rows=rows_strategy)
+def test_non_savings_taxable_income_is_the_rest_after_allowances(rows):
+    v = _calculate(rows, "ENGLAND")
+    expected = np.maximum(
+        0,
+        v["adjusted_net_income"]
+        - v["taxable_savings_interest_income"]
+        - v["taxable_dividend_income"]
+        - v["allowances"],
+    )
+    np.testing.assert_allclose(v["non_savings_taxable_income"], expected, atol=0.01)
+
+
+@SETTINGS
+@given(rows=rows_strategy, rise=st.integers(min_value=1, max_value=100_000))
+def test_more_property_income_never_lowers_savings_or_dividend_tax(rows, rise):
+    before = _calculate(rows, "ENGLAND")
+    after = _calculate(
+        [(pay, prop + rise, s, d) for pay, prop, s, d in rows], "ENGLAND"
+    )
+    for name in ["savings_income_tax", "dividend_income_tax"]:
+        assert np.all(after[name] >= before[name] - 0.01)
+
+
+def test_savings_above_property_income_past_the_basic_rate_limit_pay_the_higher_rate():
+    """£40,000 of property income leaves £10,270 of the basic-rate band, so
+    some of £20,000 of savings must pay 40%: savings tax exceeds 20% of
+    everything above the £500 savings allowance (£3,900). Main banded the
+    savings as if the property income were not there and charged £2,900."""
+    v = _calculate([(0, 40_000, 20_000, 0)] + [(0, 0, 0, 0)] * (PEOPLE - 1), "ENGLAND")
+    assert v["savings_income_tax"][0] > (20_000 - 500) * 0.20

policyengine_uk/variables/gov/hmrc/income_tax/bracketized_earned_income/non_savings_income_after_allowances.py

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+from policyengine_uk.model_api import *
+
+
+class non_savings_income_after_allowances(Variable):
+    value_type = float
+    entity = Person
+    label = "Non-savings, non-dividend income for Income Tax after allowances"
+    documentation = (
+        "Adjusted net income less savings and dividend income and allowances, "
+        "floored at nil: the income below savings and dividends (ITA 2007 s. "
+        "16) once the allowances, which go to it first, are taken off. "
+        "property_income_tax and taxable_property_income_after_allowances "
+        "both read it."
+    )
+    definition_period = YEAR
+    reference = dict(
+        title="Income Tax Act 2007, s. 16",
+        href="https://www.legislation.gov.uk/ukpga/2007/3/section/16",
+    )
+    unit = GBP
+
+    def formula(person, period, parameters):
+        return max_(
+            0,
+            person("adjusted_net_income", period)
+            - person("taxable_savings_interest_income", period)
+            - person("taxable_dividend_income", period)
+            - person("allowances", period),
+        )

policyengine_uk/variables/gov/hmrc/income_tax/bracketized_earned_income/non_savings_taxable_income.py

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+from policyengine_uk.model_api import *
+
+
+class non_savings_taxable_income(Variable):
+    value_type = float
+    entity = Person
+    label = "Taxable income other than savings and dividend income"
+    documentation = (
+        "The part of taxable income below savings and dividend income, which "
+        "ITA 2007 s. 16 treats as the highest part of total income: "
+        "earned_taxable_income plus property income after allowances. "
+        "earned_taxable_income leaves property income out because "
+        "property_income_tax taxes it separately, but property income still "
+        "fills the bands before savings and dividends do (from 2027-28, "
+        "s. 16A places it immediately below savings income). With no Marriage "
+        "Allowance it equals non_savings_income_after_allowances; "
+        "earned_taxable_income also subtracts Marriage Allowance, which the "
+        "law gives as a tax reduction (#1947)."
+    )
+    definition_period = YEAR
+    reference = [
+        dict(
+            title="Income Tax Act 2007, s. 16",
+            href="https://www.legislation.gov.uk/ukpga/2007/3/section/16",
+        ),
+        dict(
+            title="Income Tax Act 2007, s. 16A (from 2027-28)",
+            href="https://www.legislation.gov.uk/ukpga/2007/3/section/16A",
+        ),
+    ]
+    unit = GBP
+
+    def formula(person, period, parameters):
+        return person("earned_taxable_income", period) + person(
+            "taxable_property_income_after_allowances", period
+        )

policyengine_uk/variables/gov/hmrc/income_tax/bracketized_earned_income/taxable_property_income_after_allowances.py

@@ -0,0 +1,36 @@
+from policyengine_uk.model_api import *
+
+
+class taxable_property_income_after_allowances(Variable):
+    value_type = float
+    entity = Person
+    label = "Property income for Income Tax after allowances"
+    documentation = (
+        "Taxable property income less the part of the allowances it absorbs. "
+        "Allowances go to non-savings, non-dividend income first, and "
+        "property income is stacked above the rest of it, so it takes "
+        "whatever allowances the other non-savings income leaves. From "
+        "2027-28 that order is statutory: s. 25(3A) sets allowances against "
+        "income other than property, savings and dividend income first, and "
+        "s. 16A places property income immediately below savings income."
+    )
+    definition_period = YEAR
+    reference = [
+        dict(
+            title="Income Tax Act 2007, s. 25(3A) (from 2027-28)",
+            href="https://www.legislation.gov.uk/ukpga/2007/3/section/25",
+        ),
+        dict(
+            title="Income Tax Act 2007, s. 16A (from 2027-28)",
+            href="https://www.legislation.gov.uk/ukpga/2007/3/section/16A",
+        ),
+    ]
+    unit = GBP
+
+    def formula(person, period, parameters):
+        non_savings_after_allowances = person(
+            "non_savings_income_after_allowances", period
+        )
+        return min_(
+            person("taxable_property_income", period), non_savings_after_allowances
+        )