diff --git a/changelog.d/vt-2017-taxable-income.fixed.md b/changelog.d/vt-2017-taxable-income.fixed.md
new file mode 100644
index 00000000000..773a65e7d9b
--- /dev/null
+++ b/changelog.d/vt-2017-taxable-income.fixed.md
@@ -0,0 +1 @@
+Start Vermont's 2017 taxable income from federal taxable income, with the former 32 V.S.A. § 5811(21) itemized deduction addback, additions and subtractions, and add the 2017 federal standard deduction amounts.
diff --git a/policyengine_us/parameters/gov/irs/deductions/standard/aged_or_blind/amount.yaml b/policyengine_us/parameters/gov/irs/deductions/standard/aged_or_blind/amount.yaml
index d78354841f2..c73dc7f2759 100644
--- a/policyengine_us/parameters/gov/irs/deductions/standard/aged_or_blind/amount.yaml
+++ b/policyengine_us/parameters/gov/irs/deductions/standard/aged_or_blind/amount.yaml
@@ -1,5 +1,8 @@
 description: Additional standard deduction for blind and aged
 SINGLE:
+  2015-01-01: 1_550
+  2016-01-01: 1_550
+  2017-01-01: 1_550
   2018-01-01: 1_600
   2019-01-01: 1_650
   2021-01-01: 1_700
@@ -9,6 +12,9 @@ SINGLE:
   2025-01-01: 2_000
   2026-01-01: 2_050
 JOINT:
+  2015-01-01: 1_250
+  2016-01-01: 1_250
+  2017-01-01: 1_250
   2018-01-01: 1_300
   2019-01-01: 1_300
   2021-01-01: 1_350
@@ -18,6 +24,9 @@ JOINT:
   2025-01-01: 1_600
   2026-01-01: 1_650
 SEPARATE:
+  2015-01-01: 1_250
+  2016-01-01: 1_250
+  2017-01-01: 1_250
   2018-01-01: 1_300
   2019-01-01: 1_300
   2021-01-01: 1_350
@@ -27,6 +36,9 @@ SEPARATE:
   2025-01-01: 1_600
   2026-01-01: 1_650
 HEAD_OF_HOUSEHOLD:
+  2015-01-01: 1_550
+  2016-01-01: 1_550
+  2017-01-01: 1_550
   2018-01-01: 1_600
   2019-01-01: 1_650
   2021-01-01: 1_700
@@ -36,6 +48,9 @@ HEAD_OF_HOUSEHOLD:
   2025-01-01: 2_000
   2026-01-01: 2_050
 SURVIVING_SPOUSE:
+  2015-01-01: 1_250
+  2016-01-01: 1_250
+  2017-01-01: 1_250
   2018-01-01: 1_300
   2019-01-01: 1_300
   2021-01-01: 1_350
@@ -52,6 +67,12 @@ metadata:
   period: year
   propagate_metadata_to_children: true
   reference:
+    - title: 2017 IRS data release (Rev. Proc. 2016-55)
+      href: https://www.irs.gov/pub/irs-drop/rp-16-55.pdf#page=15
+    - title: 2016 IRS data release (Rev. Proc. 2015-53)
+      href: https://www.irs.gov/pub/irs-drop/rp-15-53.pdf#page=14
+    - title: 2015 IRS data release (Rev. Proc. 2014-61)
+      href: https://www.irs.gov/pub/irs-drop/rp-14-61.pdf#page=13
     - title: 2026 IRS data release
       href: https://www.irs.gov/pub/irs-drop/rp-25-32.pdf#page=18
     - title: 2025 IRS data release
diff --git a/policyengine_us/parameters/gov/irs/deductions/standard/amount.yaml b/policyengine_us/parameters/gov/irs/deductions/standard/amount.yaml
index cd56afc4fd0..75562208a5a 100644
--- a/policyengine_us/parameters/gov/irs/deductions/standard/amount.yaml
+++ b/policyengine_us/parameters/gov/irs/deductions/standard/amount.yaml
@@ -1,6 +1,9 @@
 description: Federal deduction from AGI if not itemizing.
 
 SINGLE:
+  2015-01-01: 6_300
+  2016-01-01: 6_300
+  2017-01-01: 6_350
   2018-01-01: 12_000
   2019-01-01: 12_200
   2020-01-01: 12_400
@@ -11,6 +14,9 @@ SINGLE:
   2025-01-01: 15_750
   2026-01-01: 16_100
 JOINT:
+  2015-01-01: 12_600
+  2016-01-01: 12_600
+  2017-01-01: 12_700
   2018-01-01: 24_000
   2019-01-01: 24_400
   2020-01-01: 24_800
@@ -21,6 +27,9 @@ JOINT:
   2025-01-01: 31_500
   2026-01-01: 32_200
 SEPARATE:
+  2015-01-01: 6_300
+  2016-01-01: 6_300
+  2017-01-01: 6_350
   2018-01-01: 12_000
   2019-01-01: 12_200
   2020-01-01: 12_400
@@ -31,6 +40,9 @@ SEPARATE:
   2025-01-01: 15_750
   2026-01-01: 16_100
 HEAD_OF_HOUSEHOLD:
+  2015-01-01: 9_250
+  2016-01-01: 9_300
+  2017-01-01: 9_350
   2018-01-01: 18_000
   2019-01-01: 18_350
   2020-01-01: 18_650
@@ -41,6 +53,9 @@ HEAD_OF_HOUSEHOLD:
   2025-01-01: 23_625
   2026-01-01: 24_150
 SURVIVING_SPOUSE:
+  2015-01-01: 12_600
+  2016-01-01: 12_600
+  2017-01-01: 12_700
   2018-01-01: 24_000
   2019-01-01: 24_400
   2020-01-01: 24_800
@@ -76,6 +91,12 @@ metadata:
       href: https://www.irs.gov/pub/irs-drop/rp-19-44.pdf
     - title: 2019 IRS data release
       href: https://www.irs.gov/pub/irs-drop/rp-18-57.pdf
+    - title: 2017 IRS data release (Rev. Proc. 2016-55)
+      href: https://www.irs.gov/pub/irs-drop/rp-16-55.pdf#page=15
+    - title: 2016 IRS data release (Rev. Proc. 2015-53)
+      href: https://www.irs.gov/pub/irs-drop/rp-15-53.pdf#page=13
+    - title: 2015 IRS data release (Rev. Proc. 2014-61)
+      href: https://www.irs.gov/pub/irs-drop/rp-14-61.pdf#page=13
     - title: CBO Tax Parameters and Effective Marginal Tax Rates | Feb 2024
       # 1. Tax Parameters.
       href: https://www.cbo.gov/system/files/2024-02/53724-2024-02-Tax-Parameters.xlsx
diff --git a/policyengine_us/parameters/gov/states/vt/tax/income/deductions/itemized_addback/other_multiple.yaml b/policyengine_us/parameters/gov/states/vt/tax/income/deductions/itemized_addback/other_multiple.yaml
new file mode 100644
index 00000000000..b3c982cb833
--- /dev/null
+++ b/policyengine_us/parameters/gov/states/vt/tax/income/deductions/itemized_addback/other_multiple.yaml
@@ -0,0 +1,10 @@
+description: Vermont adds back itemized deductions, other than income taxes, medical expenses and charitable contributions, in excess of this multiple of the federal standard deduction, under former 32 V.S.A. § 5811(21)(A)(iv).
+values:
+  2017-01-01: 2.5
+metadata:
+  unit: /1
+  period: year
+  label: Vermont 2017 other itemized deduction addback standard deduction multiple
+  reference:
+    - title: 2017 Vt. Acts No. 73, § 13a (former 32 V.S.A. § 5811(21)(A)(iii)-(iv)) #page 21-22
+      href: https://legislature.vermont.gov/Documents/2018/Docs/ACTS/ACT073/ACT073%20As%20Enacted.pdf#page=21
diff --git a/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/additional_standard_deduction.yaml b/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/additional_standard_deduction.yaml
new file mode 100644
index 00000000000..a5dd34ab9e8
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/additional_standard_deduction.yaml
@@ -0,0 +1,73 @@
+- name: 2017 aged single filer adds $1,550
+  period: 2017
+  input:
+    filing_status: SINGLE
+    aged_blind_count: 1
+  output:
+    additional_standard_deduction: 1_550
+
+- name: 2017 aged and blind head of household adds 2 x $1,550
+  period: 2017
+  input:
+    filing_status: HEAD_OF_HOUSEHOLD
+    aged_blind_count: 2
+  output:
+    additional_standard_deduction: 3_100
+
+- name: 2017 joint filers with one aged spouse add $1,250
+  period: 2017
+  input:
+    filing_status: JOINT
+    aged_blind_count: 1
+  output:
+    additional_standard_deduction: 1_250
+
+- name: 2017 separate filer aged adds $1,250
+  period: 2017
+  input:
+    filing_status: SEPARATE
+    aged_blind_count: 1
+  output:
+    additional_standard_deduction: 1_250
+
+- name: 2017 aged surviving spouse adds $1,250
+  period: 2017
+  input:
+    filing_status: SURVIVING_SPOUSE
+    aged_blind_count: 1
+  output:
+    additional_standard_deduction: 1_250
+
+- name: 2015 single filer aged 65 adds $1,550
+  period: 2015
+  input:
+    people:
+      head:
+        age: 65
+    tax_units:
+      tax_unit:
+        members: [head]
+        filing_status: SINGLE
+  output:
+    additional_standard_deduction: 1_550
+
+- name: 2016 single filer aged 65 adds $1,550
+  period: 2016
+  input:
+    people:
+      head:
+        age: 65
+    tax_units:
+      tax_unit:
+        members: [head]
+        filing_status: SINGLE
+  output:
+    additional_standard_deduction: 1_550
+
+- name: 2018 aged single filer adds $1,600, unchanged
+  period: 2018
+  input:
+    filing_status: SINGLE
+    aged_blind_count: 1
+  output:
+    additional_standard_deduction: 1_600
diff --git a/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/basic_standard_deduction.yaml b/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/basic_standard_deduction.yaml
index a22f9f3c55d..5e63d8f9df0 100644
--- a/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/basic_standard_deduction.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/irs/deductions/standard/basic_standard_deduction.yaml
@@ -574,3 +574,73 @@
     irs_gross_income: 15_000
     basic_standard_deduction: 15_450
     tax_unit_is_required_to_file: false
+
+- name: 2017 single filer standard deduction is $6,350
+  period: 2017
+  input:
+    filing_status: SINGLE
+  output:
+    basic_standard_deduction: 6_350
+
+- name: 2017 separate filer standard deduction is $6,350
+  period: 2017
+  input:
+    filing_status: SEPARATE
+  output:
+    basic_standard_deduction: 6_350
+
+- name: 2017 head of household standard deduction is $9,350
+  period: 2017
+  input:
+    filing_status: HEAD_OF_HOUSEHOLD
+  output:
+    basic_standard_deduction: 9_350
+
+- name: 2017 joint filer standard deduction is $12,700
+  period: 2017
+  input:
+    filing_status: JOINT
+  output:
+    basic_standard_deduction: 12_700
+
+- name: 2017 surviving spouse standard deduction is $12,700
+  period: 2017
+  input:
+    filing_status: SURVIVING_SPOUSE
+  output:
+    basic_standard_deduction: 12_700
+
+- name: 2015 head of household standard deduction is $9,250
+  period: 2015
+  input:
+    filing_status: HEAD_OF_HOUSEHOLD
+  output:
+    basic_standard_deduction: 9_250
+
+- name: 2015 joint filers get a $12,600 standard deduction
+  period: 2015
+  input:
+    filing_status: JOINT
+  output:
+    basic_standard_deduction: 12_600
+
+- name: 2015 single filers get a $6,300 standard deduction
+  period: 2015
+  input:
+    filing_status: SINGLE
+  output:
+    basic_standard_deduction: 6_300
+
+- name: 2016 head of household standard deduction is $9,300
+  period: 2016
+  input:
+    filing_status: HEAD_OF_HOUSEHOLD
+  output:
+    basic_standard_deduction: 9_300
+
+- name: 2016 joint filer standard deduction is $12,600
+  period: 2016
+  input:
+    filing_status: JOINT
+  output:
+    basic_standard_deduction: 12_600
diff --git a/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_itemized_deduction_addback.yaml b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_itemized_deduction_addback.yaml
new file mode 100644
index 00000000000..671bdc0aa63
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_itemized_deduction_addback.yaml
@@ -0,0 +1,263 @@
+- name: A 2017 nonitemizer adds nothing back.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: false
+    itemized_taxable_income_deductions: 30_000
+    standard_deduction: 6_350
+    salt_deduction: 2_000
+    state_withheld_income_tax: 2_000
+  output:
+    vt_2017_itemized_deduction_addback: 0
+
+- name: 2017 adds back income taxes and other deductions above 2.5 times the standard deduction.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    itemized_taxable_income_deductions: 30_000
+    standard_deduction: 6_350
+    salt_deduction: 2_000
+    state_withheld_income_tax: 2_000
+    medical_expense_deduction: 0
+    charitable_deduction: 0
+  output:
+    # min(2,000, 30,000 - 6,350) + max(30,000 - 2,000 - 2.5 x 6,350, 0)
+    # = 2,000 + 12,125
+    vt_2017_itemized_deduction_addback: 14_125
+
+- name: 2017 income tax addback is limited to itemized deductions above the standard deduction.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    itemized_taxable_income_deductions: 7_000
+    standard_deduction: 6_350
+    salt_deduction: 3_000
+    state_withheld_income_tax: 3_000
+    medical_expense_deduction: 0
+    charitable_deduction: 0
+  output:
+    # min(3,000, 650) + max(7,000 - 3,000 - 15,875, 0)
+    vt_2017_itemized_deduction_addback: 650
+
+- name: 2017 sales tax deducted instead of income tax is not added back.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    itemized_taxable_income_deductions: 25_000
+    standard_deduction: 6_350
+    salt_deduction: 3_000
+    state_withheld_income_tax: 1_000
+    state_sales_tax: 3_000
+    medical_expense_deduction: 2_000
+    charitable_deduction: 3_000
+  output:
+    # T = 0; max(25,000 - 0 - 2,000 - 3,000 - 15,875, 0) = 4,125
+    vt_2017_itemized_deduction_addback: 4_125
+
+- name: 2017 medical and charitable deductions are not in the other-deduction pool.
+  period: 2017
+  input:
+    state_code: VT
+    filing_status: JOINT
+    tax_unit_itemizes: true
+    itemized_taxable_income_deductions: 40_000
+    standard_deduction: 12_700
+    salt_deduction: 5_000
+    state_withheld_income_tax: 5_000
+    medical_expense_deduction: 10_000
+    charitable_deduction: 5_000
+  output:
+    # min(5,000, 27,300) + max(40,000 - 5,000 - 10,000 - 5,000 - 31,750, 0)
+    vt_2017_itemized_deduction_addback: 5_000
+
+- name: The addback only applies in 2017.
+  period: 2018
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    itemized_taxable_income_deductions: 30_000
+    standard_deduction: 12_000
+    salt_deduction: 2_000
+    state_withheld_income_tax: 2_000
+  output:
+    vt_2017_itemized_deduction_addback: 0
+
+- name: 2017 counts wagering losses among the other itemized deductions.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    itemized_taxable_income_deductions: 12_850
+    wagering_losses_deduction: 30_000
+    standard_deduction: 6_350
+    salt_deduction: 4_850
+    state_withheld_income_tax: 4_850
+    medical_expense_deduction: 0
+    charitable_deduction: 0
+  output:
+    # IN-155 line 1 takes Schedule A line 29, so I = 12,850 + 30,000 = 42,850.
+    # min(4,850, 42,850 - 6,350) + max(42,850 - 4,850 - 2.5 x 6,350, 0)
+    # = 4,850 + 22,125
+    vt_2017_itemized_deduction_addback: 26_975
+
+- name: 2017 scales deducted income taxes by the share section 68 leaves.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    total_itemized_taxable_income_deductions: 44_000
+    itemized_taxable_income_deductions_reduction: 4_000
+    itemized_taxable_income_deductions: 40_000
+    standard_deduction: 6_350
+    salt_deduction: 20_000
+    state_withheld_income_tax: 20_000
+    medical_expense_deduction: 4_000
+    charitable_deduction: 10_000
+  output:
+    # Limited base 44,000 - 4,000 medical = 40,000; r = 1 - 4,000 / 40,000 = 0.9.
+    # T = 18,000, C = 9,000.
+    # min(18,000, 40,000 - 6,350) + max(40,000 - 18,000 - 4,000 - 9,000 - 15,875, 0)
+    # = 18,000 + 0 (unscaled: 20,000)
+    vt_2017_itemized_deduction_addback: 18_000
+
+- name: 2017 scales charitable deductions by the share section 68 leaves.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    total_itemized_taxable_income_deductions: 74_000
+    itemized_taxable_income_deductions_reduction: 7_000
+    itemized_taxable_income_deductions: 67_000
+    standard_deduction: 6_350
+    salt_deduction: 20_000
+    state_withheld_income_tax: 20_000
+    medical_expense_deduction: 4_000
+    charitable_deduction: 10_000
+  output:
+    # Limited base 74,000 - 4,000 = 70,000; r = 1 - 7,000 / 70,000 = 0.9.
+    # T = 18,000, C = 9,000.
+    # min(18,000, 67,000 - 6,350) + max(67,000 - 18,000 - 4,000 - 9,000 - 15,875, 0)
+    # = 18,000 + 20,125 (unscaled: 37,125)
+    vt_2017_itemized_deduction_addback: 38_125
+
+- name: 2017 leaves income taxes whole when no deductions are subject to section 68.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    total_itemized_taxable_income_deductions: 8_000
+    itemized_taxable_income_deductions_reduction: 0
+    itemized_taxable_income_deductions: 8_000
+    standard_deduction: 6_350
+    salt_deduction: 2_000
+    state_withheld_income_tax: 2_000
+    medical_expense_deduction: 8_000
+    charitable_deduction: 0
+  output:
+    # Limited base max(8,000 - 8,000, 0) = 0, so r = 1.
+    # min(2,000, 8,000 - 6,350) + max(8,000 - 2,000 - 8,000 - 15,875, 0) = 1,650
+    vt_2017_itemized_deduction_addback: 1_650
+
+- name: 2017 addback through the section 68 limitation, end to end.
+  period: 2017
+  absolute_error_margin: 0.01
+  input:
+    state_code: VT
+    tax_unit_itemizes: true
+    adjusted_gross_income: 500_000
+    salt_deduction: 20_000
+    state_withheld_income_tax: 20_000
+    charitable_deduction: 10_000
+    medical_expense_deduction: 4_000
+    interest_deduction: 40_000
+    standard_deduction: 6_350
+  output:
+    # Total 20,000 + 10,000 + 4,000 + 40,000 = 74,000; limited base 70,000.
+    # Reduction min((500,000 - 261,500) x 3%, 80% x 70,000) = 7,155.
+    # I = 66,845; r = 62,845 / 70,000.
+    # T = 17,955.71, C = 8,977.86.
+    # min(17,955.71, 60,495) + max(66,845 - 17,955.71 - 4,000 - 8,977.86 - 15,875, 0)
+    # = 17,955.71 + 20,036.43
+    itemized_taxable_income_deductions_reduction: 7_155
+    itemized_taxable_income_deductions: 66_845
+    vt_2017_itemized_deduction_addback: 37_992.14
+
+- name: 2017 separate filer whose spouse doesn't itemize measures the addback against the standard deduction.
+  period: 2017
+  absolute_error_margin: 0.01
+  input:
+    state_code: VT
+    filing_status: SEPARATE
+    tax_unit_itemizes: true
+    separate_filer_itemizes: false
+    employment_income: 100_000
+    real_estate_taxes: 8_000
+    state_withheld_income_tax: 4_850
+  output:
+    # Schedule A line 29: 4,850 state income tax + 8,000 real estate tax
+    # = 12,850, with no section 68 cut.
+    # Line 1 12,850; line 2 6,350; line 3 6,500.
+    # Line 4 4,850; lines 5 and 6 0; line 7 4,850.
+    # Line 8 8,000; line 9 2.5 x 6,350 = 15,875; line 10 0.
+    # Line 11 min(6,500, 4,850) + 0 = 4,850.
+    standard_deduction: 6_350
+    vt_2017_itemized_deduction_addback: 4_850
+    # 100,000 - 4,050 exemption - 12,850 itemized + 4,850 addback
+    vt_taxable_income: 87_950
+
+- name: 2017 separate filer whose spouse itemizes has no standard deduction on line 2.
+  period: 2017
+  absolute_error_margin: 0.01
+  input:
+    state_code: VT
+    filing_status: SEPARATE
+    tax_unit_itemizes: true
+    separate_filer_itemizes: true
+    employment_income: 100_000
+    real_estate_taxes: 8_000
+    state_withheld_income_tax: 4_850
+  output:
+    # The filer's spouse itemizes, so the filer's standard deduction falls
+    # to 0 (26 U.S.C. 63(c)(6)(A)). Schedule A line 29: 12,850, as in the
+    # case above.
+    # Line 1 12,850; line 2 0; line 3 12,850.
+    # Line 4 4,850; lines 5 and 6 0; line 7 4,850.
+    # Line 8 8,000; line 9 0; line 10 8,000.
+    # Line 11 min(12,850, 4,850) + 8,000 = 12,850.
+    standard_deduction: 0
+    vt_2017_itemized_deduction_addback: 12_850
+    # 100,000 - 4,050 exemption - 12,850 itemized + 12,850 addback
+    vt_taxable_income: 95_950
+
+- name: 2017 single filer aged 65 adds the aged amount to line 2.
+  period: 2017
+  absolute_error_margin: 0.01
+  input:
+    people:
+      head:
+        age: 65
+        employment_income: 100_000
+        real_estate_taxes: 20_000
+    tax_units:
+      tax_unit:
+        members: [head]
+        filing_status: SINGLE
+        tax_unit_itemizes: true
+        state_withheld_income_tax: 4_850
+    households:
+      household:
+        members: [head]
+        state_code: VT
+  output:
+    # Line 1 4,850 + 20,000 = 24,850; line 2 6,350 + 1,550 aged = 7,900;
+    # line 3 16,950. Line 4 4,850; line 8 20,000; line 9 2.5 x 7,900 =
+    # 19,750; line 10 250. Line 11 min(16,950, 4,850) + 250 = 5,100.
+    # Without the aged amount, line 9 would come to 15,875 and the
+    # addback to 8,975.
+    standard_deduction: 7_900
+    vt_2017_itemized_deduction_addback: 5_100
+    # 100,000 - 4,050 - 24,850 + 5,100
+    vt_taxable_income: 76_200
diff --git a/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_other_additions.yaml b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_other_additions.yaml
new file mode 100644
index 00000000000..bddb1aa2f3e
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_other_additions.yaml
@@ -0,0 +1,8 @@
+- name: 2017 other additions total tax-exempt interest and other additions.
+  period: 2017
+  input:
+    state_code: VT
+    tax_exempt_interest_income: 1_500
+    vt_other_additions: 700
+  output:
+    vt_2017_other_additions: 2_200
diff --git a/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_subtractions.yaml b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_subtractions.yaml
new file mode 100644
index 00000000000..d42e347da8f
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/deductions/vt_2017_subtractions.yaml
@@ -0,0 +1,17 @@
+- name: 2017 subtractions total U.S. obligation interest, taxable state refunds and other subtractions.
+  period: 2017
+  input:
+    state_code: VT
+    us_govt_interest: 1_000
+    salt_refund_income: 300
+    vt_2017_other_subtractions: 2_000
+  output:
+    vt_2017_subtractions: 3_300
+
+- name: No subtractions outside Vermont.
+  period: 2017
+  input:
+    state_code: NH
+    us_govt_interest: 1_000
+  output:
+    vt_2017_subtractions: 0
diff --git a/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/vt_taxable_income.yaml b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/vt_taxable_income.yaml
index 548e36c989c..2a82cd9db15 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/vt_taxable_income.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/vt_taxable_income.yaml
@@ -34,3 +34,129 @@
     state_code: VT
   output:
     vt_taxable_income: 0
+
+- name: 2017 uses federal deductions and historical adjustments.
+  period: 2017
+  input:
+    state_code: VT
+    adjusted_gross_income: 50_000
+    exemptions: 4_050
+    taxable_income_deductions: 20_000
+    vt_2017_itemized_deduction_addback: 2_000
+    vt_2017_other_additions: 1_000
+    vt_2017_subtractions: 500
+    # The 2018+ Vermont-base inputs below do not enter 2017 taxable income.
+    vt_agi: 49_500
+    vt_standard_deduction: 6_350
+    vt_personal_exemptions: 4_050
+  output:
+    # 50,000 - 4,050 - 20,000 + 2,000 + 1,000 - 500
+    vt_taxable_income: 28_450
+
+- name: 2017 restores excess other itemized deductions.
+  period: 2017
+  input:
+    state_code: VT
+    adjusted_gross_income: 70_000
+    exemptions: 4_050
+    taxable_income_deductions: 30_000
+    vt_2017_itemized_deduction_addback: 14_125
+    vt_2017_other_additions: 0
+    vt_2017_subtractions: 0
+  output:
+    # 70,000 - 4,050 - 30,000 + 14,125
+    vt_taxable_income: 50_075
+
+- name: 2017 keeps a negative federal base before Vermont additions.
+  period: 2017
+  input:
+    state_code: VT
+    adjusted_gross_income: 5_000
+    exemptions: 4_050
+    taxable_income_deductions: 6_350
+    taxable_income: 0
+    vt_2017_itemized_deduction_addback: 0
+    vt_2017_other_additions: 1_000
+    vt_2017_subtractions: 0
+  output:
+    # 5,000 - 4,050 - 6,350 + 1,000 = -4,400, floored at zero. Starting
+    # from floored federal taxable income would give $1,000.
+    vt_taxable_income: 0
+
+- name: 2017 subtractions cannot push taxable income below zero.
+  period: 2017
+  input:
+    state_code: VT
+    adjusted_gross_income: 20_000
+    exemptions: 4_050
+    taxable_income_deductions: 6_350
+    vt_2017_itemized_deduction_addback: 0
+    vt_2017_other_additions: 0
+    vt_2017_subtractions: 15_000
+  output:
+    vt_taxable_income: 0
+
+- name: 2018 still starts from Vermont AGI.
+  period: 2018
+  input:
+    state_code: VT
+    adjusted_gross_income: 50_000
+    exemptions: 0
+    taxable_income_deductions: 20_000
+    vt_agi: 40_000
+    vt_standard_deduction: 6_000
+    vt_personal_exemptions: 4_000
+  output:
+    vt_taxable_income: 30_000
+
+- name: 2016 keeps the Vermont-base formula.
+  period: 2016
+  input:
+    state_code: VT
+    adjusted_gross_income: 50_000
+    exemptions: 0
+    taxable_income_deductions: 20_000
+    vt_agi: 45_000
+    vt_standard_deduction: 6_000
+    vt_personal_exemptions: 4_000
+  output:
+    # 45,000 - 6,000 - 4,000. The 2017 federal base would give
+    # 50,000 - 0 - 20,000 = 30,000, and no formula would give 0.
+    vt_taxable_income: 35_000
+
+- name: 2017 starts from the federal base, not Vermont AGI less Vermont deductions.
+  period: 2017
+  input:
+    state_code: VT
+    tax_unit_itemizes: false
+    adjusted_gross_income: 50_000
+    exemptions: 4_050
+    taxable_income_deductions: 20_000
+    vt_agi: 49_500
+    vt_standard_deduction: 6_350
+    vt_personal_exemptions: 4_050
+  output:
+    # 50,000 - 4,050 - 20,000, with no addback, additions or subtractions.
+    # The Vermont-base formula would give 49,500 - 6,350 - 4,050 = 39,100.
+    vt_taxable_income: 25_950
+
+- name: 2017 single wage earner, end to end from the federal base.
+  period: 2017
+  absolute_error_margin: 0.01
+  input:
+    people:
+      head:
+        age: 40
+        employment_income: 60_000
+    tax_units:
+      tax_unit:
+        members: [head]
+    households:
+      household:
+        members: [head]
+        state_code: VT
+  output:
+    # 60,000 - 4,050 exemption - 6,350 standard deduction.
+    standard_deduction: 6_350
+    exemptions: 4_050
+    vt_taxable_income: 49_600
diff --git a/policyengine_us/tests/test_vt_2017_taxable_income_properties.py b/policyengine_us/tests/test_vt_2017_taxable_income_properties.py
new file mode 100644
index 00000000000..1cceb17a680
--- /dev/null
+++ b/policyengine_us/tests/test_vt_2017_taxable_income_properties.py
@@ -0,0 +1,243 @@
+"""Property tests: Vermont's 2017 taxable income under former 32 V.S.A.
+§ 5811(21).
+
+For 2017, Vermont taxable income is federal taxable income, before its zero
+floor, plus the itemized deduction addback and other additions, less the
+subtractions, floored at zero. Schedule IN-155 computes the addback. For
+allowed federal itemized deductions I (Schedule A line 29, after section 68
+and including wagering losses), deducted income taxes T, medical M,
+charitable C and federal standard deduction S, it is min(rT, max(I - S, 0))
++ max(I - rT - M - rC - 2.5 S, 0) for an itemizer and zero otherwise. r is
+the Department's worksheet ratio: the share of the deductions section 68
+limits that remains after the limitation (1 when none are limited).
+
+Properties checked, each in one batched simulation per example:
+
+1. max(I - SALT - M - C - 2.5 S, 0) <= addback <= max(I - S, 0) +
+   max(I - 2.5 S, 0) for an itemizer, and the addback is zero for a
+   nonitemizer.
+2. The addback never falls when I rises with T, M, C, S and r held fixed.
+3. The addback matches in155_line_11, a reference that follows Schedule
+   IN-155 lines 1 to 11 and the worksheet's cells L8 to L10.
+4. vt_taxable_income >= 0, and does not depend on the 2018+ Vermont base
+   (vt_agi, vt_standard_deduction, vt_personal_exemptions).
+5. Raising the other additions by d raises vt_taxable_income by between 0
+   and d, and by exactly d when the original value is positive.
+
+Properties 4 and 5 fail if 2017 uses the 2018+ formula, which ignores the
+additions and reads the Vermont base. The model computes in single
+precision, so comparisons allow one cent or eight float32 spacings.
+"""
+
+import numpy as np
+from hypothesis import HealthCheck, given, settings
+from hypothesis import strategies as st
+
+from policyengine_us import Simulation
+
+YEAR = 2017
+MAX_AMOUNT = 100_000
+SETTINGS = settings(
+    max_examples=15,
+    deadline=None,
+    suppress_health_check=[HealthCheck.too_slow],
+)
+
+amount = st.integers(min_value=0, max_value=MAX_AMOUNT)
+
+
+def tolerance(*amounts):
+    scale = np.float32(max(np.max(np.abs(a)) for a in amounts))
+    return max(0.01, 8 * float(np.spacing(scale)))
+
+
+def calculate(units, variable):
+    """One Vermont tax unit per household, each with its own inputs."""
+    people, tax_units, households = {}, {}, {}
+    for i, unit in enumerate(units):
+        people[f"p{i}"] = {"age": {YEAR: 40}}
+        tax_units[f"t{i}"] = {
+            "members": [f"p{i}"],
+            **{name: {YEAR: value} for name, value in unit.items()},
+        }
+        households[f"h{i}"] = {
+            "members": [f"p{i}"],
+            "state_code": {YEAR: "VT"},
+        }
+    situation = {
+        "people": people,
+        "tax_units": tax_units,
+        "households": households,
+    }
+    return Simulation(situation=situation).calculate(variable, YEAR)
+
+
+def complete_addback_unit(draw):
+    """Build total itemized deductions from their parts, and draw the section
+    68 reduction within its ceiling: 80% of the deductions it limits."""
+    unit = dict(draw)
+    unit["total_itemized_taxable_income_deductions"] = total = (
+        unit["salt_deduction"]
+        + unit["medical_expense_deduction"]
+        + unit["charitable_deduction"]
+        + unit.pop("other_itemized")
+    )
+    ceiling = 0.8 * max(total - unit["medical_expense_deduction"], 0)
+    reduction = round(unit.pop("reduction_share") * ceiling)
+    unit["itemized_taxable_income_deductions_reduction"] = reduction
+    unit["itemized_taxable_income_deductions"] = total - reduction
+    return unit
+
+
+addback_unit = st.fixed_dictionaries(
+    {
+        "tax_unit_itemizes": st.booleans(),
+        "other_itemized": amount,
+        "reduction_share": st.sampled_from([0, 0.25, 0.5, 1]),
+        "wagering_losses_deduction": st.one_of(st.just(0), amount),
+        "standard_deduction": st.integers(min_value=0, max_value=20_000),
+        "salt_deduction": amount,
+        "state_withheld_income_tax": amount,
+        "local_income_tax": st.just(0),
+        "state_sales_tax": amount,
+        "local_sales_tax": st.just(0),
+        "medical_expense_deduction": amount,
+        "charitable_deduction": amount,
+    }
+).map(complete_addback_unit)
+
+
+def itemized_total(unit):
+    return (
+        unit["itemized_taxable_income_deductions"] + unit["wagering_losses_deduction"]
+    )
+
+
+def in155_line_11(unit):
+    """The 2017 Schedule IN-155 addback, line by line, with the Department's
+    worksheet for limited itemized deductions on lines 4 and 6."""
+    if not unit["tax_unit_itemizes"]:
+        return 0.0
+    # Worksheet: L8 total deductions, L9 deductions not limited at the
+    # federal level (medical and wagering losses here), L10 total deductions
+    # after limitations.
+    l8 = (
+        unit["total_itemized_taxable_income_deductions"]
+        + unit["wagering_losses_deduction"]
+    )
+    l9 = unit["medical_expense_deduction"] + unit["wagering_losses_deduction"]
+    l10 = itemized_total(unit)
+    ratio = (l10 - l9) / (l8 - l9) if l8 > l9 else 1.0
+    # Schedule A line 5a holds income taxes only when the filer elects them
+    # over sales taxes.
+    income_taxes = unit["state_withheld_income_tax"] + unit["local_income_tax"]
+    sales_taxes = unit["state_sales_tax"] + unit["local_sales_tax"]
+    schedule_a_5a = (
+        min(income_taxes, unit["salt_deduction"]) if income_taxes >= sales_taxes else 0
+    )
+    line_1 = itemized_total(unit)  # Schedule A line 29
+    line_2 = unit["standard_deduction"]
+    # A filer whose itemized deductions are below the standard deduction has
+    # nothing to add back on line 3.
+    line_3 = max(line_1 - line_2, 0)
+    line_4 = schedule_a_5a * ratio
+    line_5 = unit["medical_expense_deduction"]
+    line_6 = unit["charitable_deduction"] * ratio
+    line_7 = line_4 + line_5 + line_6
+    line_8 = line_1 - line_7
+    line_9 = line_2 * 2.5
+    line_10 = max(line_8 - line_9, 0)
+    return min(line_3, line_4) + line_10
+
+
+@SETTINGS
+@given(units=st.lists(addback_unit, min_size=1, max_size=20), raise_by=amount)
+def test_addback_bounds_and_monotonicity(units, raise_by):
+    addback = calculate(units, "vt_2017_itemized_deduction_addback")
+    itemized = np.array([itemized_total(u) for u in units])
+    standard = np.array([u["standard_deduction"] for u in units])
+    itemizes = np.array([u["tax_unit_itemizes"] for u in units])
+    upper = np.maximum(itemized - standard, 0) + np.maximum(
+        itemized - 2.5 * standard, 0
+    )
+    eps = tolerance(addback, upper)
+    assert np.all(addback >= -eps)
+    assert np.all(addback <= upper + eps)
+    assert np.all(np.abs(addback[~itemizes]) <= eps)
+    # Scaled income taxes are at most the SALT deduction, so the other
+    # deductions are at least I - SALT - M - C.
+    salt = np.array([u["salt_deduction"] for u in units])
+    medical = np.array([u["medical_expense_deduction"] for u in units])
+    charitable = np.array([u["charitable_deduction"] for u in units])
+    lower = np.maximum(itemized - salt - medical - charitable - 2.5 * standard, 0)
+    assert np.all(addback[itemizes] >= lower[itemizes] - eps)
+
+    raised = [
+        {
+            **u,
+            "itemized_taxable_income_deductions": u[
+                "itemized_taxable_income_deductions"
+            ]
+            + raise_by,
+        }
+        for u in units
+    ]
+    raised_addback = calculate(raised, "vt_2017_itemized_deduction_addback")
+    assert np.all(raised_addback >= addback - tolerance(addback, raised_addback))
+
+
+@SETTINGS
+@given(units=st.lists(addback_unit, min_size=1, max_size=20))
+def test_addback_matches_schedule_in155(units):
+    addback = calculate(units, "vt_2017_itemized_deduction_addback")
+    expected = np.array([in155_line_11(u) for u in units])
+    assert np.all(np.abs(addback - expected) <= tolerance(addback, expected))
+
+
+taxable_income_unit = st.fixed_dictionaries(
+    {
+        "adjusted_gross_income": st.integers(min_value=-20_000, max_value=MAX_AMOUNT),
+        "exemptions": st.integers(min_value=0, max_value=20_000),
+        "taxable_income_deductions": st.integers(min_value=0, max_value=50_000),
+        "vt_2017_itemized_deduction_addback": st.integers(
+            min_value=0, max_value=20_000
+        ),
+        "vt_2017_other_additions": st.integers(min_value=0, max_value=20_000),
+        "vt_2017_subtractions": st.integers(min_value=0, max_value=20_000),
+        "vt_agi": amount,
+        "vt_standard_deduction": st.integers(min_value=0, max_value=20_000),
+        "vt_personal_exemptions": st.integers(min_value=0, max_value=20_000),
+    }
+)
+
+
+@SETTINGS
+@given(
+    units=st.lists(taxable_income_unit, min_size=1, max_size=20),
+    vermont_base_shift=st.integers(min_value=1, max_value=50_000),
+    raise_by=st.integers(min_value=1, max_value=20_000),
+)
+def test_taxable_income_floor_base_and_additions(units, vermont_base_shift, raise_by):
+    taxable = calculate(units, "vt_taxable_income")
+    assert np.all(taxable >= 0)
+
+    shifted = [{**u, "vt_agi": u["vt_agi"] + vermont_base_shift} for u in units]
+    shifted_taxable = calculate(shifted, "vt_taxable_income")
+    assert np.all(
+        np.abs(shifted_taxable - taxable) <= tolerance(taxable, shifted_taxable)
+    )
+
+    raised = [
+        {
+            **u,
+            "vt_2017_other_additions": u["vt_2017_other_additions"] + raise_by,
+        }
+        for u in units
+    ]
+    raised_taxable = calculate(raised, "vt_taxable_income")
+    change = raised_taxable - taxable
+    eps = tolerance(taxable, raised_taxable)
+    assert np.all(change >= -eps)
+    assert np.all(change <= raise_by + eps)
+    positive = taxable > eps
+    assert np.all(np.abs(change[positive] - raise_by) <= eps)
diff --git a/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_itemized_deduction_addback.py b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_itemized_deduction_addback.py
new file mode 100644
index 00000000000..7f4cf5fffbd
--- /dev/null
+++ b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_itemized_deduction_addback.py
@@ -0,0 +1,75 @@
+from policyengine_us.model_api import *
+
+
+class vt_2017_itemized_deduction_addback(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Vermont 2017 itemized deduction addback"
+    unit = USD
+    documentation = (
+        "Federal itemized deductions Vermont adds back to 2017 federal "
+        "taxable income, following Schedule IN-155: deducted state and local "
+        "income taxes, up to the itemized deductions above the federal "
+        "standard deduction, plus other itemized deductions (excluding "
+        "medical and charitable) above 2.5 times the federal standard "
+        "deduction. Itemized deductions include wagering losses and are after "
+        "the section 68 limitation, which also scales the income taxes and "
+        "charity."
+    )
+    definition_period = YEAR
+    defined_for = StateCode.VT
+    reference = (
+        # Former 32 V.S.A. § 5811(21)(A)(iii)-(iv), reproduced in 2017 Vt.
+        # Acts No. 73, § 13a. PDF pages 21-22.
+        "https://legislature.vermont.gov/Documents/2018/Docs/ACTS/ACT073/ACT073%20As%20Enacted.pdf#page=21",
+        # 2017 Schedule IN-155 and the Department's 2017 worksheet for limited
+        # itemized deductions.
+        "https://web.archive.org/web/20250629013817/https://tax.vermont.gov/sites/tax/files/documents/IN-155-2017.pdf",
+        "https://web.archive.org/web/20201019064237/https://tax.vermont.gov/sites/tax/files/documents/2017%20IN-155%20Worksheet.xlsx",
+    )
+
+    def formula_2017(tax_unit, period, parameters):
+        p = parameters(period).gov.states.vt.tax.income.deductions.itemized_addback
+        itemizes = tax_unit("tax_unit_itemizes", period)
+        # IN-155 line 1 takes Schedule A line 29: allowed itemized deductions
+        # after the section 68 limitation, including wagering losses, which
+        # itemized_taxable_income_deductions leaves out.
+        itemized = add(
+            tax_unit,
+            period,
+            ["itemized_taxable_income_deductions", "wagering_losses_deduction"],
+        )
+        standard = tax_unit("standard_deduction", period)
+        # The SALT deduction holds income taxes only when they exceed sales
+        # taxes (state_and_local_sales_or_income_tax takes the larger).
+        income_taxes = add(
+            tax_unit, period, ["state_withheld_income_tax", "local_income_tax"]
+        )
+        sales_taxes = add(tax_unit, period, ["state_sales_tax", "local_sales_tax"])
+        salt = tax_unit("salt_deduction", period)
+        deducted_income_taxes = where(
+            income_taxes >= sales_taxes, min_(income_taxes, salt), 0
+        )
+        # The Department's worksheet for limited itemized deductions scales
+        # income taxes and charity by the share of the limited deductions that
+        # section 68 leaves. Section 68(c) doesn't limit medical expenses.
+        limitation = parameters(period).gov.irs.deductions.itemized.limitation
+        total = tax_unit("total_itemized_taxable_income_deductions", period)
+        excluded = add(tax_unit, period, limitation.excluded_deductions)
+        limited = max_(total - excluded, 0)
+        reduction = tax_unit("itemized_taxable_income_deductions_reduction", period)
+        remaining_share = 1 - np.divide(
+            reduction, limited, out=np.zeros_like(limited), where=limited > 0
+        )
+        allowed_income_taxes = deducted_income_taxes * remaining_share
+        allowed_charitable = tax_unit("charitable_deduction", period) * remaining_share
+        medical = tax_unit("medical_expense_deduction", period)
+        income_tax_addback = min_(allowed_income_taxes, max_(itemized - standard, 0))
+        other_deductions = (
+            itemized - allowed_income_taxes - medical - allowed_charitable
+        )
+        other_addback = max_(other_deductions - p.other_multiple * standard, 0)
+        return where(itemizes, income_tax_addback + other_addback, 0)
+
+    def formula_2018(tax_unit, period, parameters):
+        return 0
diff --git a/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_other_additions.py b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_other_additions.py
new file mode 100644
index 00000000000..ce2b2e8b263
--- /dev/null
+++ b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_other_additions.py
@@ -0,0 +1,23 @@
+from policyengine_us.model_api import *
+
+
+class vt_2017_other_additions(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Vermont 2017 additions to federal taxable income"
+    unit = USD
+    documentation = (
+        "Vermont's 2017 additions to federal taxable income other than the "
+        "itemized deduction addback: interest on non-Vermont state and local "
+        "obligations and the adjustment for federal bonus depreciation under "
+        "26 U.S.C. § 168(k). As in Vermont's AGI additions, all tax-exempt "
+        "interest is added; vt_other_additions carries the rest."
+    )
+    definition_period = YEAR
+    defined_for = StateCode.VT
+    reference = (
+        # Former 32 V.S.A. § 5811(21), as amended by 2015 Vt. Acts No. 57, § 64.
+        "https://legislature.vermont.gov/Documents/2016/Docs/ACTS/ACT057/ACT057%20As%20Enacted.pdf#page=89",
+    )
+
+    adds = ["tax_exempt_interest_income", "vt_other_additions"]
diff --git a/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_other_subtractions.py b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_other_subtractions.py
new file mode 100644
index 00000000000..8c6af95d4ac
--- /dev/null
+++ b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_other_subtractions.py
@@ -0,0 +1,21 @@
+from policyengine_us.model_api import *
+
+
+class vt_2017_other_subtractions(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Vermont 2017 other subtractions from federal taxable income"
+    unit = USD
+    documentation = (
+        "Vermont's 2017 subtractions from federal taxable income that "
+        "PolicyEngine does not calculate, entered as a positive amount: the "
+        "capital gains exclusion under the law then in effect and the "
+        "depreciation adjustment for property whose federal bonus "
+        "depreciation was added back in an earlier year."
+    )
+    definition_period = YEAR
+    defined_for = StateCode.VT
+    reference = (
+        # Former 32 V.S.A. § 5811(21), as amended by 2015 Vt. Acts No. 57, § 64.
+        "https://legislature.vermont.gov/Documents/2016/Docs/ACTS/ACT057/ACT057%20As%20Enacted.pdf#page=89",
+    )
diff --git a/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_subtractions.py b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_subtractions.py
new file mode 100644
index 00000000000..4ce44f8e6eb
--- /dev/null
+++ b/policyengine_us/variables/gov/states/vt/tax/income/deductions/vt_2017_subtractions.py
@@ -0,0 +1,22 @@
+from policyengine_us.model_api import *
+
+
+class vt_2017_subtractions(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "Vermont 2017 subtractions from federal taxable income"
+    unit = USD
+    documentation = (
+        "Vermont's 2017 subtractions from federal taxable income: income from "
+        "U.S. obligations, taxable state and local income tax refunds, and "
+        "other subtractions such as the capital gains exclusion and "
+        "depreciation adjustments for property placed in service earlier."
+    )
+    definition_period = YEAR
+    defined_for = StateCode.VT
+    reference = (
+        # Former 32 V.S.A. § 5811(21), as amended by 2015 Vt. Acts No. 57, § 64.
+        "https://legislature.vermont.gov/Documents/2016/Docs/ACTS/ACT057/ACT057%20As%20Enacted.pdf#page=89",
+    )
+
+    adds = ["us_govt_interest", "salt_refund_income", "vt_2017_other_subtractions"]
diff --git a/policyengine_us/variables/gov/states/vt/tax/income/vt_taxable_income.py b/policyengine_us/variables/gov/states/vt/tax/income/vt_taxable_income.py
index 771e9c3949e..43da19a2ee7 100644
--- a/policyengine_us/variables/gov/states/vt/tax/income/vt_taxable_income.py
+++ b/policyengine_us/variables/gov/states/vt/tax/income/vt_taxable_income.py
@@ -6,13 +6,44 @@ class vt_taxable_income(Variable):
     entity = TaxUnit
     label = "Vermont taxable income"
     unit = USD
-    documentation = "VT AGI less taxable income deductions and exemptions"
+    documentation = (
+        "Before 2017 and from 2018, Vermont AGI less the Vermont standard "
+        "deduction and personal exemptions. In 2017, federal taxable income with Vermont's "
+        "additions and subtractions under former 32 V.S.A. § 5811(21)."
+    )
     definition_period = YEAR
-    reference = "https://tax.vermont.gov/sites/tax/files/documents/IN-111-2022.pdf"
+    reference = (
+        "https://tax.vermont.gov/sites/tax/files/documents/IN-111-2022.pdf",
+        # Former 32 V.S.A. § 5811(21), as amended by 2015 Vt. Acts No. 57, § 64.
+        "https://legislature.vermont.gov/Documents/2016/Docs/ACTS/ACT057/ACT057%20As%20Enacted.pdf#page=89",
+        # 2017 Vt. Acts No. 73, § 13a reproduces the former text; § 32(5)
+        # changes the base from 2018. PDF pages 21-22, 59.
+        "https://legislature.vermont.gov/Documents/2018/Docs/ACTS/ACT073/ACT073%20As%20Enacted.pdf#page=21",
+        "https://web.archive.org/web/2018/https://tax.vermont.gov/sites/tax/files/documents/IN-111%20Instr-2017.pdf#page=5",
+    )
     defined_for = StateCode.VT
 
-    def formula(tax_unit, period, parameters):
+    def formula_2017(tax_unit, period, parameters):
+        # Federal taxable income before its zero floor, so that a negative
+        # federal base offsets Vermont's additions.
+        agi = tax_unit("adjusted_gross_income", period)
+        exemptions = tax_unit("exemptions", period)
+        deductions = tax_unit("taxable_income_deductions", period)
+        federal_base = agi - exemptions - deductions
+        additions = add(
+            tax_unit,
+            period,
+            ["vt_2017_itemized_deduction_addback", "vt_2017_other_additions"],
+        )
+        subtractions = tax_unit("vt_2017_subtractions", period)
+        return max_(0, federal_base + additions - subtractions)
+
+    def formula_2018(tax_unit, period, parameters):
         agi = tax_unit("vt_agi", period)
         deductions = tax_unit("vt_standard_deduction", period)
         exemptions = tax_unit("vt_personal_exemptions", period)
         return max_(0, agi - deductions - exemptions)
+
+    # Before 2017, keep the Vermont-base formula. Former § 5811(21) also set
+    # the federal base for 2015 and 2016, which this variable doesn't model.
+    formula = formula_2018