From cf5be2cbb445e2374f1cbebe63fbe669a62a4e03 Mon Sep 17 00:00:00 2001 From: David Trimmer Date: Wed, 26 Aug 2026 09:40:25 -0400 Subject: [PATCH 1/2] Remove Montana property tax rebate from non-refundable credit list The Montana Property Tax Rebate (up to $675 for TY2022-2023) is a standalone rebate claimed on a separate application to the Department of Revenue, not a Form 2 nonrefundable income-tax credit. It was listed in gov.states.mt.tax.income.credits.non_refundable, so it reduced Montana income tax; and because the person-level aggregator mt_non_refundable_credits adds the tax-unit-level $675 rebate, PolicyEngine projected it onto every household member (e.g. $675 x 3 = $2,025 for a family of three), understating MT tax. Remove it from the 2022-01-01 credit list, leaving mt_capital_gain_credit. The rebate variable still computes its $675 value; it simply no longer reduces income tax. Restores mt_income_tax to 5,708.16 for the issue household (was 3,683.16), matching the TaxAct return. Fixes #9347. Co-Authored-By: Claude Opus 4.8 Claude-Session: https://claude.ai/code/session_018ECQhxDkVchXm1RNVyqwnx --- changelog_entry.yaml | 4 +++ .../mt/tax/income/credits/non_refundable.yaml | 1 - .../gov/states/mt/tax/income/integration.yaml | 36 +++++++++++++++++++ 3 files changed, 40 insertions(+), 1 deletion(-) create mode 100644 changelog_entry.yaml diff --git a/changelog_entry.yaml b/changelog_entry.yaml new file mode 100644 index 00000000000..872e8ebe233 --- /dev/null +++ b/changelog_entry.yaml @@ -0,0 +1,4 @@ +- bump: patch + changes: + fixed: + - Removed the Montana property tax rebate from the state non-refundable credit list so it no longer reduces Montana income tax. diff --git a/policyengine_us/parameters/gov/states/mt/tax/income/credits/non_refundable.yaml b/policyengine_us/parameters/gov/states/mt/tax/income/credits/non_refundable.yaml index 8c79519aa4c..bbd61f3ed1e 100644 --- a/policyengine_us/parameters/gov/states/mt/tax/income/credits/non_refundable.yaml +++ b/policyengine_us/parameters/gov/states/mt/tax/income/credits/non_refundable.yaml @@ -5,7 +5,6 @@ values: - mt_income_tax_rebate 2022-01-01: - mt_capital_gain_credit - - mt_property_tax_rebate 2024-01-01: [] metadata: unit: list diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/integration.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/integration.yaml index 83209df9ad4..9b610d880c9 100644 --- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/integration.yaml +++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/integration.yaml @@ -567,3 +567,39 @@ # Files separately: 5,099.51 - 1,250 + 3,719.51 - 1,250 = 6,319.02 # (old double-count subtracted $2,500 per column, understating tax by $2,500) mt_income_tax: 6_319.02 + +- name: MT property tax rebate is not a Form 2 credit and is not tripled (issue 9347) + absolute_error_margin: 0.01 + period: 2023 + input: + people: + person1: + is_tax_unit_head: true + age: 26 + employment_income: 110_625.07 + taxable_interest_income: 204.41 + real_estate_taxes: 2_754.52 + person2: + is_tax_unit_spouse: true + age: 25 + employment_income: 3_414.32 + person3: + is_tax_unit_dependent: true + age: 10 + tax_units: + tax_unit: + members: [person1, person2, person3] + spm_units: + spm_unit: + members: [person1, person2, person3] + households: + household: + members: [person1, person2, person3] + state_fips: 30 + output: + # The $675 standalone property tax rebate is still computed as its own variable + mt_property_tax_rebate: 675 + # but it is not a Form 2 non-refundable credit. Before the fix it was booked + # as a credit and projected onto every household member (675 x 3 = 2,025), + # understating Montana income tax; it must contribute 0 to each person. + mt_non_refundable_credits: [0, 0, 0] From 3066fdce840330ef55ddab14dab4e30046e9fd4f Mon Sep 17 00:00:00 2001 From: David Trimmer Date: Wed, 26 Aug 2026 10:44:39 -0400 Subject: [PATCH 2/2] Use changelog.d fragment instead of changelog_entry.yaml Co-Authored-By: Claude Opus 4.8 Claude-Session: https://claude.ai/code/session_018ECQhxDkVchXm1RNVyqwnx --- changelog.d/mt-property-tax-rebate.fixed.md | 1 + changelog_entry.yaml | 4 ---- 2 files changed, 1 insertion(+), 4 deletions(-) create mode 100644 changelog.d/mt-property-tax-rebate.fixed.md delete mode 100644 changelog_entry.yaml diff --git a/changelog.d/mt-property-tax-rebate.fixed.md b/changelog.d/mt-property-tax-rebate.fixed.md new file mode 100644 index 00000000000..9f3214451af --- /dev/null +++ b/changelog.d/mt-property-tax-rebate.fixed.md @@ -0,0 +1 @@ +Removed the Montana property tax rebate from the state non-refundable credit list so it no longer reduces Montana income tax. diff --git a/changelog_entry.yaml b/changelog_entry.yaml deleted file mode 100644 index 872e8ebe233..00000000000 --- a/changelog_entry.yaml +++ /dev/null @@ -1,4 +0,0 @@ -- bump: patch - changes: - fixed: - - Removed the Montana property tax rebate from the state non-refundable credit list so it no longer reduces Montana income tax.