Montana Personal Income Tax Schedule

changelog_entry.yaml

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+- bump: minor
+  changes:
+    added:
+    - Montana personal income tax schedule. 

policyengine_us/parameters/gov/states/mt/tax/income/main/head_of_household.yaml

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+description: Montana taxes head of household filers at this rate structure.
+metadata:
+  type: marginal_rate
+  threshold_unit: currency-USD
+  rate_unit: /1
+  label: Montana income tax rates for head of household filers
+  reference:
+    - title: Montana Code Annotated 2021 Title 15, Chapter 30, Part 21, 15-30-2103 
+      href: https://leg.mt.gov/bills/mca/title_0150/chapter_0300/part_0210/section_0030/0150-0300-0210-0030.html
+# Before 2024 Montana has a flat tax rate for each filing status
+# After 2024 the tax rate depends on the filing status
+brackets:
+  - threshold:
+      2021-01-01: 0
+    rate:
+      2021-01-01: 0.01
+      2024-01-01: 0.047
+  - threshold:
+      2021-01-01: 2_900
+      2022-01-01: 3_300
+      2024-01-01: 30_750
+    rate:
+      2021-01-01: 0.02
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 5_100
+      2022-01-01: 5_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.03
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 7_800
+      2022-01-01: 8_900
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.04
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 10_500
+      2022-01-01: 12_000
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.05
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 13_500
+      2022-01-01: 15_400
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.06
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 17_400
+      2022-01-01: 19_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.0675
+      2024-01-01: 0.065

policyengine_us/parameters/gov/states/mt/tax/income/main/joint.yaml

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+description: Montana taxes joint filers at this rate structure.
+metadata:
+  type: marginal_rate
+  threshold_unit: currency-USD
+  rate_unit: /1
+  label: Montana income tax rate joint filers
+  reference:
+    - title: Montana Code Annotated 2021 Title 15, Chapter 30, Part 21, 15-30-2103 
+      href: https://leg.mt.gov/bills/mca/title_0150/chapter_0300/part_0210/section_0030/0150-0300-0210-0030.html
+# Before 2024 Montana has a flat tax rate for each filing status
+# After 2024 the tax rate depends on the filing status
+brackets:
+  - threshold:
+      2021-01-01: 0
+    rate:
+      2021-01-01: 0.01
+      2024-01-01: 0.047
+  - threshold:
+      2021-01-01: 2_900
+      2022-01-01: 3_300
+      2024-01-01: 41_000
+    rate:
+      2021-01-01: 0.02
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 5_100
+      2022-01-01: 5_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.03
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 7_800
+      2022-01-01: 8_900
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.04
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 10_500
+      2022-01-01: 12_000
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.05
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 13_500
+      2022-01-01: 15_400
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.06
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 17_400
+      2022-01-01: 19_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.0675
+      2024-01-01: 0.065

policyengine_us/parameters/gov/states/mt/tax/income/main/separate.yaml

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+description: Montana taxes separate filers at this rate structure.
+metadata:
+  type: marginal_rate
+  threshold_unit: currency-USD
+  rate_unit: /1
+  label: Montana income tax rate separate filers
+  reference:
+    - title: Montana Code Annotated 2021 Title 15, Chapter 30, Part 21, 15-30-2103 
+      href: https://leg.mt.gov/bills/mca/title_0150/chapter_0300/part_0210/section_0030/0150-0300-0210-0030.html
+# Before 2024 Montana has a flat tax rate for each filing status
+# After 2024 the tax rate depends on the filing status
+brackets:
+  - threshold:
+      2021-01-01: 0
+    rate:
+      2021-01-01: 0.01
+      2024-01-01: 0.047
+  - threshold:
+      2021-01-01: 2_900
+      2022-01-01: 3_300
+      2024-01-01: 20_500
+    rate:
+      2021-01-01: 0.02
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 5_100
+      2022-01-01: 5_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.03
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 7_800
+      2022-01-01: 8_900
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.04
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 10_500
+      2022-01-01: 12_000
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.05
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 13_500
+      2022-01-01: 15_400
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.06
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 17_400
+      2022-01-01: 19_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.0675
+      2024-01-01: 0.065

policyengine_us/parameters/gov/states/mt/tax/income/main/single.yaml

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+description: Montana taxes single filers at this rate structure.
+metadata:
+  type: marginal_rate
+  threshold_unit: currency-USD
+  rate_unit: /1
+  label: Montana income tax rate single filers
+  reference:
+    - title: Montana Code Annotated 2021 Title 15, Chapter 30, Part 21, 15-30-2103 
+      href: https://leg.mt.gov/bills/mca/title_0150/chapter_0300/part_0210/section_0030/0150-0300-0210-0030.html
+# Before 2024 Montana has a flat tax rate for each filing status
+# After 2024 the tax rate depends on the filing status
+brackets:
+  - threshold:
+      2021-01-01: 0
+    rate:
+      2021-01-01: 0.01
+      2024-01-01: 0.047
+  - threshold:
+      2021-01-01: 2_900
+      2022-01-01: 3_300
+      2024-01-01: 20_500
+    rate:
+      2021-01-01: 0.02
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 5_100
+      2022-01-01: 5_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.03
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 7_800
+      2022-01-01: 8_900
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.04
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 10_500
+      2022-01-01: 12_000
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.05
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 13_500
+      2022-01-01: 15_400
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.06
+      2024-01-01: 0.065
+  - threshold:
+      2021-01-01: 17_400
+      2022-01-01: 19_800
+      2024-01-01: .inf
+    rate:
+      2021-01-01: 0.0675
+      2024-01-01: 0.065

policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/mt_income_tax_before_refundable_credits.yaml

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+- name: No income 
+  period: 2021
+  input:
+     filing_status: SINGLE
+     mt_taxable_income: 0
+     state_code: MT
+  output:
+    mt_income_tax_before_refundable_credits: 0
+
+- name: Temporary rate calculation #((5_000 - 2_900) * 0.02 + 2_900 * 0.01)
+  period: 2021
+  input:
+     filing_status: SINGLE
+     mt_taxable_income: 5_000
+     state_code: MT
+  output:
+    mt_income_tax_before_refundable_credits: 71
+
+- name: Progressive rate - Joint filing # 5_000 * 0.047
+  period: 2024
+  input:
+     filing_status: JOINT
+     mt_taxable_income: 5_000
+     state_code: MT
+  output:
+    mt_income_tax_before_refundable_credits: 235
+
+- name: Progressive rate - Single filing # ((25_000 - 20_500) * 0.065 + 20_500 * 0.047)
+  period: 2025
+  input:
+     filing_status: SINGLE
+     mt_taxable_income: 25_000
+     state_code: MT
+  output:
+    mt_income_tax_before_refundable_credits: 1_256
+
+- name: Progressive rate - head of household # ((35_000 - 30_750) * 0.065 + 30_750 * 0.047)
+  period: 2025
+  input:
+     filing_status: HEAD_OF_HOUSEHOLD
+     mt_taxable_income: 35_000
+     state_code: MT
+  output:
+    mt_income_tax_before_refundable_credits: 1_721.5

policyengine_us/variables/gov/states/mt/tax/income/mt_income_tax.py

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+from policyengine_us.model_api import *
+
+
+class mt_income_tax(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Montana income tax"
+    unit = USD
+    definition_period = YEAR
+    defined_for = StateCode.MT
+    adds = ["mt_income_tax_before_refundable_credits"]
+    subtracts = ["mt_refundable_credits"]

policyengine_us/variables/gov/states/mt/tax/income/mt_income_tax_before_refundable_credits.py

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+from policyengine_us.model_api import *
+
+
+class mt_income_tax_before_refundable_credits(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Montana income tax before refundable credits"
+    unit = USD
+    definition_period = YEAR
+    defined_for = StateCode.MT
+
+    def formula(tax_unit, period, parameters):
+        income = tax_unit("mt_taxable_income", period)
+        p = parameters(period).gov.states.mt.tax.income.main
+        filing_status = tax_unit("filing_status", period)
+        status = filing_status.possible_values
+        return select(
+            [
+                filing_status == status.SINGLE,
+                filing_status == status.JOINT,
+                filing_status == status.HEAD_OF_HOUSEHOLD,
+                filing_status == status.SEPARATE,
+            ],
+            [
+                p.single.calc(income),
+                p.joint.calc(income),
+                p.head_of_household.calc(income),
+                p.separate.calc(income),
+            ],
+        )

policyengine_us/variables/gov/states/mt/tax/income/mt_refundable_credits.py

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+from policyengine_us.model_api import *
+
+
+class mt_refundable_credits(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Montana refundable credits"
+    unit = USD
+    definition_period = YEAR
+    defined_for = StateCode.MT

policyengine_us/variables/gov/states/mt/tax/income/mt_taxable_income.py

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+from policyengine_us.model_api import *
+
+
+class mt_taxable_income(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Montana taxable income"
+    unit = USD
+    definition_period = YEAR
+    defined_for = StateCode.MT

policyengine_us/variables/gov/states/ri/tax/income/ri_refundable_credits.py

@@ -1,7 +1,7 @@
 from policyengine_us.model_api import *
 
 
-class ri_refunable_credits(Variable):
+class ri_refundable_credits(Variable):
     value_type = float
     entity = TaxUnit
     label = "Rhode Island refundable credits"