MaxGhenis · Oct 6, 2026 · Oct 9, 2026 · Oct 11, 2026 · Oct 11, 2026 · Oct 11, 2026
diff --git a/changelog.d/corporate-sdlt-once.fixed.md b/changelog.d/corporate-sdlt-once.fixed.md
@@ -0,0 +1 @@
+- Count corporate SDLT once in `household_tax`, `gov_tax` and `pre_budget_change_household_tax`. `expected_sdlt` no longer adds `corporate_sdlt`, which those totals already list. `gov.hmrc.stamp_duty.abolish` now zeroes `corporate_sdlt` and the `stamp_duty_land_tax` liability (no household is `sdlt_liable` once the tax is abolished) as well as `expected_sdlt`, so abolishing SDLT removes all of it. `expected_sdlt` also no longer adds `property_sale_rate` (a 0.045 share) to every household as £0.045 of SDLT.
diff --git a/changelog.d/fiscal-partition.added.md b/changelog.d/fiscal-partition.added.md
@@ -0,0 +1 @@
+- Add `policyengine_uk/data/fiscal_partition.yaml`, a tax-head partition of `gov_tax`, `household_tax` and `pre_budget_change_household_tax`: one row of the OBR current receipts table per head, the rows the model does not cover, explicit exclusions and overlap guards. Tests check that each total is the sum of its heads and counts each head once.
diff --git a/policyengine_uk/data/fiscal_partition.yaml b/policyengine_uk/data/fiscal_partition.yaml
diff --git a/...ngine_uk/tests/policy/baseline/gov/hmrc/council_tax/high_value_council_tax_surcharge.yaml b/...ngine_uk/tests/policy/baseline/gov/hmrc/council_tax/high_value_council_tax_surcharge.yaml
@@ -7,7 +7,6 @@
     main_residential_property_purchased: 0
     council_tax: 0
     household_owns_tv: false
-    gov.hmrc.stamp_duty.property_sale_rate: 0
   output:
     high_value_council_tax_surcharge: 0
 - name: High value council tax surcharge applies in England and flows into aggregates
@@ -19,7 +18,6 @@
     main_residential_property_purchased: 0
     council_tax: 0
     household_owns_tv: false
-    gov.hmrc.stamp_duty.property_sale_rate: 0
   output:
     high_value_council_tax_surcharge: 2_500
     household_tax: 2_500
@@ -34,7 +32,6 @@
     main_residential_property_purchased: 0
     council_tax: 0
     household_owns_tv: false
-    gov.hmrc.stamp_duty.property_sale_rate: 0
   output:
     high_value_council_tax_surcharge: 2_550
     household_tax: 2_550
@@ -48,7 +45,6 @@
     main_residential_property_purchased: 0
     council_tax: 0
     household_owns_tv: false
-    gov.hmrc.stamp_duty.property_sale_rate: 0
   output:
     high_value_council_tax_surcharge: 0
     household_tax: 0
@@ -63,7 +59,6 @@
     main_residential_property_purchased: 0
     council_tax: 1_500
     household_owns_tv: false
-    gov.hmrc.stamp_duty.property_sale_rate: 0
   output:
     high_value_council_tax_surcharge: 2_500
     household_tax: 0

diff --git a/policyengine_uk/tests/policy/baseline/gov/hmrc/stamp_duty/corporate_sdlt.yaml b/policyengine_uk/tests/policy/baseline/gov/hmrc/stamp_duty/corporate_sdlt.yaml
@@ -0,0 +1,168 @@
+# Corporate SDLT is shareholding x (residential + non-residential corporate
+# SDLT revenue) = shareholding x (£705m + £2,425m) = shareholding x £3,130m
+# (gov.hmrc.stamp_duty.statistics, 2020 values held flat). A shareholding of
+# 1e-6 gives £3,130 and 3e-6 gives £9,390. business_rates is set to 0 so the
+# totals isolate SDLT. A £500,000 purchase that is not a first home pays
+# £15,000 of SDLT (see expected_sdlt.yaml).
+- name: Corporate SDLT enters household and government taxes once
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    region: LONDON
+    shareholding: 0.000001
+    business_rates: 0
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    corporate_sdlt: 3_130
+    expected_sdlt: 0
+    corporate_tax_incidence: 3_130
+    household_tax: 3_130
+    gov_tax: 3_130
+    pre_budget_change_household_tax: 3_130
+- name: Household and corporate SDLT each enter the totals once
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    region: LONDON
+    main_residential_property_purchased: 500_000
+    main_residential_property_purchased_is_first_home: false
+    shareholding: 0.000001
+    business_rates: 0
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    expected_sdlt: 15_000
+    corporate_sdlt: 3_130
+    household_tax: 18_130
+    gov_tax: 18_130
+    pre_budget_change_household_tax: 18_130
+- name: Abolishing SDLT removes household and corporate SDLT from the totals
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    gov.hmrc.stamp_duty.abolish: true
+    region: LONDON
+    main_residential_property_purchased: 500_000
+    main_residential_property_purchased_is_first_home: false
+    shareholding: 0.000001
+    business_rates: 0
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    stamp_duty_land_tax: 0
+    expected_sdlt: 0
+    corporate_sdlt: 0
+    corporate_tax_incidence: 0
+    household_tax: 0
+    gov_tax: 0
+    pre_budget_change_household_tax: 0
+- name: Two households, baseline - each household's SDLT counted once
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      buyer:
+        age: 40
+      shareholder:
+        age: 60
+    benunits:
+      benunit_1:
+        members: [buyer]
+      benunit_2:
+        members: [shareholder]
+    households:
+      household_1:
+        members: [buyer]
+        region: LONDON
+        main_residential_property_purchased: 500_000
+        main_residential_property_purchased_is_first_home: false
+        shareholding: 0.000001
+        business_rates: 0
+        council_tax: 0
+        household_owns_tv: false
+      household_2:
+        members: [shareholder]
+        region: SCOTLAND
+        shareholding: 0.000003
+        business_rates: 0
+        council_tax: 0
+        household_owns_tv: false
+  output:
+    expected_sdlt: [15_000, 0]
+    corporate_sdlt: [3_130, 9_390]
+    household_tax: [18_130, 9_390]
+    gov_tax: [18_130, 9_390]
+- name: Two households, SDLT abolished - no SDLT left in either household's totals
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    gov.hmrc.stamp_duty.abolish: true
+    people:
+      buyer:
+        age: 40
+      shareholder:
+        age: 60
+    benunits:
+      benunit_1:
+        members: [buyer]
+      benunit_2:
+        members: [shareholder]
+    households:
+      household_1:
+        members: [buyer]
+        region: LONDON
+        main_residential_property_purchased: 500_000
+        main_residential_property_purchased_is_first_home: false
+        shareholding: 0.000001
+        business_rates: 0
+        council_tax: 0
+        household_owns_tv: false
+      household_2:
+        members: [shareholder]
+        region: SCOTLAND
+        shareholding: 0.000003
+        business_rates: 0
+        council_tax: 0
+        household_owns_tv: false
+  output:
+    expected_sdlt: [0, 0]
+    corporate_sdlt: [0, 0]
+    household_tax: [0, 0]
+    gov_tax: [0, 0]
+# Abolition removes SDLT and nothing else. Corporate SDLT reaches shareholders
+# wherever they live; business rates, the other corporate tax allocated by
+# shareholding, stays.
+- name: A Welsh shareholder bears corporate SDLT and business rates, each once
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    region: WALES
+    shareholding: 0.000001
+    business_rates: 500
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    expected_sdlt: 0
+    corporate_sdlt: 3_130
+    corporate_tax_incidence: 3_630
+    household_tax: 3_630
+    gov_tax: 3_630
+    pre_budget_change_household_tax: 3_630
+- name: Abolishing SDLT removes the Welsh shareholder's corporate SDLT and keeps business rates
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    gov.hmrc.stamp_duty.abolish: true
+    region: WALES
+    shareholding: 0.000001
+    business_rates: 500
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    expected_sdlt: 0
+    corporate_sdlt: 0
+    corporate_tax_incidence: 500
+    household_tax: 500
+    gov_tax: 500
+    pre_budget_change_household_tax: 500
diff --git a/policyengine_uk/tests/policy/baseline/gov/hmrc/stamp_duty/expected_sdlt.yaml b/policyengine_uk/tests/policy/baseline/gov/hmrc/stamp_duty/expected_sdlt.yaml
@@ -0,0 +1,82 @@
+# expected_sdlt is the household's own SDLT, with nothing added to it.
+# Residential rates from 1 April 2025 (gov.uk/stamp-duty-land-tax/residential-property-rates):
+# 0% to £125,000; 2% to £250,000; 5% to £925,000. A £500,000 purchase that is
+# not a first home pays 2% x £125,000 + 5% x £250,000 = £15,000.
+- name: No purchase and no corporate wealth means no SDLT in the tax totals (England)
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    region: LONDON
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    stamp_duty_land_tax: 0
+    expected_sdlt: 0
+    corporate_sdlt: 0
+    household_tax: 0
+    gov_tax: 0
+- name: No SDLT in the tax totals of a household outside England and Northern Ireland (Scotland)
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    region: SCOTLAND
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    expected_sdlt: 0
+    household_tax: 0
+    gov_tax: 0
+- name: No SDLT in the tax totals of a household outside England and Northern Ireland (Wales)
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    region: WALES
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    expected_sdlt: 0
+    household_tax: 0
+    gov_tax: 0
+- name: Expected SDLT on a purchase equals the SDLT liability
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    region: LONDON
+    main_residential_property_purchased: 500_000
+    main_residential_property_purchased_is_first_home: false
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    stamp_duty_land_tax: 15_000
+    expected_sdlt: 15_000
+    household_tax: 15_000
+    gov_tax: 15_000
+- name: Abolishing SDLT zeroes the liability and expected SDLT
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    gov.hmrc.stamp_duty.abolish: true
+    region: LONDON
+    main_residential_property_purchased: 500_000
+    main_residential_property_purchased_is_first_home: false
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    sdlt_liable: false
+    stamp_duty_land_tax: 0
+    expected_sdlt: 0
+    household_tax: 0
+    gov_tax: 0
+- name: Abolishing SDLT zeroes expected SDLT even when the liability is entered directly
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    gov.hmrc.stamp_duty.abolish: true
+    region: LONDON
+    stamp_duty_land_tax: 15_000
+    council_tax: 0
+    household_owns_tv: false
+  output:
+    expected_sdlt: 0
+    household_tax: 0
+    gov_tax: 0
diff --git a/policyengine_uk/tests/policy/baseline/gov/hmrc/stamp_duty/sdlt_liable.yaml b/policyengine_uk/tests/policy/baseline/gov/hmrc/stamp_duty/sdlt_liable.yaml
@@ -4,3 +4,10 @@
     country: [ENGLAND, WALES, SCOTLAND, NORTHERN_IRELAND]
   output:
     sdlt_liable: [true, false, false, true]
+- name: No household is liable once Stamp Duty is abolished
+  period: 2026
+  input:
+    gov.hmrc.stamp_duty.abolish: true
+    country: [ENGLAND, WALES, SCOTLAND, NORTHERN_IRELAND]
+  output:
+    sdlt_liable: [false, false, false, false]
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Count corporate SDLT once in `household_tax`, `gov_tax` and `pre_budget_change_household_tax`. `expected_sdlt` no longer adds `corporate_sdlt`, which those totals already list. `gov.hmrc.stamp_duty.abolish` now zeroes `corporate_sdlt` and the `stamp_duty_land_tax` liability (no household is `sdlt_liable` once the tax is abolished) as well as `expected_sdlt`, so abolishing SDLT removes all of it. `expected_sdlt` also no longer adds `property_sale_rate` (a 0.045 share) to every household as £0.045 of SDLT.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Add `policyengine_uk/data/fiscal_partition.yaml`, a tax-head partition of `gov_tax`, `household_tax` and `pre_budget_change_household_tax`: one row of the OBR current receipts table per head, the rows the model does not cover, explicit exclusions and overlap guards. Tests check that each total is the sum of its heads and counts each head once.