From 29c153ecd7f5deb48727c91d86eea552fae6f15f Mon Sep 17 00:00:00 2001
From: Max Ghenis <max@policyengine.org>
Date: Mon, 12 Oct 2026 05:15:59 -0400
Subject: [PATCH 1/6] Count a filer's gains without netted losses and Social
 Security once in Montana elderly credit income

Gross household income is federal AGI "without regard to loss" (MCA
15-30-2337(9)(a)); 2024 Schedule 2EC line 7 says "do not include any
capital losses". The loss add-back restores only loss_ald, which holds the
capital loss deducted in AGI. A filer's short-term loss netted against
their own long-term gain never reaches it, so a member on their own return
with a $10,000 long-term gain and a $4,000 short-term loss counted $6,000;
as a dependent the same person counted $10,000. Restore the netted loss for
everyone who is not a tax unit dependent, as dependent_gross_income does.

The untaxed Social Security add-back subtracted both taxable_social_security
and dependent_taxable_social_security. A person input as a dependent who is
also the head (every adult in the unit input as a dependent) has neither
counted, so part of their benefits dropped out. Subtract only the taxable
part that irs_gross_income or dependent_gross_income actually counted.

Review findings S1 (DTrim99) and P2 (GPT-6.1 Sol) on
PolicyEngine/policyengine-us#9882, whose changes landed in #9915.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .../fix-mt-ehrc-filer-gains-ss-roles.fixed.md |  1 +
 .../gross_income_sources.yaml                 |  9 ++--
 ...or_renter_credit_gross_household_income.py | 42 +++++++++++++++----
 3 files changed, 40 insertions(+), 12 deletions(-)
 create mode 100644 changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md

diff --git a/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md b/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md
new file mode 100644
index 00000000000..4a3ddef2131
--- /dev/null
+++ b/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md
@@ -0,0 +1 @@
+Montana's elderly homeowner/renter credit now counts a filer's capital gains without the losses netted against them on the same return, and counts Social Security once when a person is input as both a tax unit dependent and the head.
diff --git a/policyengine_us/parameters/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/gross_income_sources.yaml b/policyengine_us/parameters/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/gross_income_sources.yaml
index 7c3c2184cdf..cf106919fa7 100644
--- a/policyengine_us/parameters/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/gross_income_sources.yaml
+++ b/policyengine_us/parameters/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/gross_income_sources.yaml
@@ -80,8 +80,11 @@ values:
     - mt_elderly_homeowner_or_renter_credit_received
     - mt_elderly_homeowner_or_renter_credit_federal_refundable_credits
     - mt_elderly_homeowner_or_renter_credit_property_tax_rebate_received
-# Social Security under § 15-30-2337(9)(a)(viii) is added separately in
-# mt_elderly_homeowner_or_renter_credit_gross_household_income.py because the
-# untaxed portion is computed as social_security - taxable_social_security.
+# mt_elderly_homeowner_or_renter_credit_gross_household_income.py adds three
+# items separately: a tax unit dependent's own gross income (their income is
+# on their own return, not in adjusted_gross_income_person); the untaxed
+# portion of Social Security under § 15-30-2337(9)(a)(viii), computed as
+# social_security less the taxable part already counted; and the losses
+# deducted in federal AGI.
 # This year's elderly homeowner/renter credit is excluded to avoid a circular
 # reference; the credit received during the year counts instead.
diff --git a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
index c6f1065035f..1f10e5273a5 100644
--- a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
+++ b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
@@ -53,16 +53,20 @@ def formula(person, period, parameters):
             person("dependent_gross_income", period) - own_deductions
         )
         # The income above counts only the taxable portion of Social
-        # Security: a filer's in federal AGI, a dependent's in their own
-        # gross income. Add the untaxed portion so all SS is counted per
-        # § 15-30-2337(9)(a)(viii).
+        # Security: a filer's in federal AGI (irs_gross_income counts people
+        # who are not dependents), a dependent's in their own gross income
+        # (dependent_gross_income counts people who are not the head or
+        # spouse). Subtract only the part one of them counted, then add the
+        # rest, so all SS is counted once per § 15-30-2337(9)(a)(viii) even
+        # when a person is input as both a dependent and the head.
         social_security = person("social_security", period)
-        taxable_social_security = add(
-            person,
-            period,
-            ["taxable_social_security", "dependent_taxable_social_security"],
+        head_or_spouse = person("is_tax_unit_head_or_spouse", period)
+        counted_social_security = where(
+            is_dependent,
+            ~head_or_spouse * person("dependent_taxable_social_security", period),
+            person("taxable_social_security", period),
         )
-        untaxed_social_security = max_(social_security - taxable_social_security, 0)
+        untaxed_social_security = max_(social_security - counted_social_security, 0)
         # Income is federal AGI "without regard to loss" (§ 15-30-2337(9)(a)),
         # so the business and capital losses deducted in computing federal
         # AGI are added back (2023 Elderly Homeowner/Renter Credit Schedule,
@@ -70,4 +74,24 @@ def formula(person, period, parameters):
         # losses."). The return's losses are added once, to the head.
         head = person("is_tax_unit_head", period)
         losses = head * person.tax_unit("loss_ald", period)
-        return sources + dependent_income + untaxed_social_security + losses
+        # loss_ald holds only the capital loss deducted in AGI. A filer's
+        # short-term loss netted against their own long-term gain (or the
+        # reverse) never reaches it, so restore that loss here: count each
+        # gain without its losses, as the dependent path does and as 2024
+        # Schedule 2EC line 7 requires ("do not include any capital
+        # losses"). Taking the larger of the floored parts and the net keeps
+        # a capital_gains value supplied directly as an input.
+        long_term_gains = max_(0, person("long_term_capital_gains", period))
+        short_term_gains = max_(0, person("short_term_capital_gains", period))
+        capital_gains = person("capital_gains", period)
+        gains_without_losses = max_(long_term_gains + short_term_gains, capital_gains)
+        netted_capital_loss = ~is_dependent * (
+            gains_without_losses - max_(0, capital_gains)
+        )
+        return (
+            sources
+            + dependent_income
+            + untaxed_social_security
+            + losses
+            + netted_capital_loss
+        )

From 88e09fef0dff3ee6485c61410a1f614d86a48998 Mon Sep 17 00:00:00 2001
From: Max Ghenis <max@policyengine.org>
Date: Mon, 12 Oct 2026 05:21:50 -0400
Subject: [PATCH 2/6] Add Schedule 2EC cases for netted gains, the dependent
 gate and overlapping roles

Four cases fail on main (a filer's and a claimant's netted capital loss,
Social Security for a person input as both dependent and head, and the
credit-level netting case); five guard behavior main already has (the
dependent gate for a minor alone in a tax unit, a business loss on another
member's return, cross-spouse netting on a joint return, and a dependent in
another member's tax unit).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 ...mt_elderly_homeowner_or_renter_credit.yaml |  85 +++++++++
 ..._renter_credit_gross_household_income.yaml | 173 ++++++++++++++++++
 2 files changed, 258 insertions(+)

diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
index 472a0218dd0..0891f65af24 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
@@ -580,3 +580,88 @@
     # = 1_099.89; line 21 = 100%; line 22 = 1_099.89.
     mt_elderly_homeowner_or_renter_credit_net_household_income: [900.11, 0]
     mt_elderly_homeowner_or_renter_credit: [1_099.89, 0]
+
+- name: 2024 Schedule 2EC, a household member's netted capital loss does not raise the credit
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        real_estate_taxes: 2_000
+      person2:
+        age: 30
+        long_term_capital_gains: 10_000
+        short_term_capital_gains: -4_000
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # Line 5 = 20_000; line 17 = 10_000 (the gain without the loss); line
+    # 18 = 30_000; line 20 = 17_400; line 22 = 17_400 x 0.05 = 870; line 27 =
+    # 2_000 - 870 = 1_130; line 29 = 100%; line 30 = 1_130. Netting the loss
+    # would give line 18 = 26_000, line 22 = 670 and the 1_150 cap.
+    mt_elderly_homeowner_or_renter_credit_net_household_income: [870, 0]
+    mt_elderly_homeowner_or_renter_credit: [1_130, 0]
+
+- name: 2024 Schedule 2EC, a capital loss netted between spouses on a joint return is added back once
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: 10_000
+        real_estate_taxes: 2_000
+      person2:
+        age: 68
+        short_term_capital_gains: -4_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # Federal AGI 20_000 + 10_000 - 4_000 = 26_000; the 4_000 loss is added
+    # back once. Line 18 = 30_000; line 22 = 870; line 30 = 1_130.
+    mt_elderly_homeowner_or_renter_credit_net_household_income: [870, 0]
+    mt_elderly_homeowner_or_renter_credit: [1_130, 0]
+
+- name: 2024 Schedule 2EC, a minor filing alone in the household counts once
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        real_estate_taxes: 2_000
+        is_tax_unit_dependent: false
+      person2:
+        age: 16
+        employment_income: 10_000
+        is_tax_unit_dependent: false
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # Line 18 = 20_000 + 10_000 = 30_000; line 30 = 1_130. Counting the
+    # minor's wages twice would give 40_000, line 22 = 1_370 and a credit of
+    # (2_000 - 1_370) x 30% = 189.
+    mt_elderly_homeowner_or_renter_credit: [1_130, 0]
diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
index ec00f8c2fad..502bfc29e52 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
@@ -336,3 +336,176 @@
     # extent that the amount recovered reduced the claimant's Montana income
     # tax in a prior year".
     mt_elderly_homeowner_or_renter_credit_gross_household_income: 10_000
+
+- name: A filer's short-term loss netted against their own long-term gain does not reduce gross household income
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+      person2:
+        age: 30
+        long_term_capital_gains: 10_000
+        short_term_capital_gains: -4_000
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # § 15-30-2337(9)(a): federal AGI "without regard to loss"; 2024
+    # Schedule 2EC line 7: "do not include any capital losses". The member's
+    # own return nets the 4_000 loss into a 6_000 gain, so no loss reaches
+    # loss_ald; line 17 still carries the 10_000 gain.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
+
+- name: A claimant's short-term loss netted against their own long-term gain does not reduce gross household income
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: 10_000
+        short_term_capital_gains: -4_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # Line 5 pensions 20_000 plus line 7 capital gain 10_000, without the
+    # 4_000 loss: 30_000.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 30_000
+
+- name: A minor alone in a tax unit and not input as a dependent counts once
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        is_tax_unit_dependent: false
+      person2:
+        age: 16
+        employment_income: 10_000
+        is_tax_unit_dependent: false
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # The minor is neither head (no adult in the unit), spouse nor
+    # dependent. irs_gross_income counts people who are not dependents and
+    # dependent_gross_income people who are not the head or spouse, so only
+    # the dependent gate keeps the 10_000 wages from counting twice.
+    is_tax_unit_head: [true, false]
+    is_tax_unit_dependent: [false, false]
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
+
+- name: Social Security counts in full for a person input as a dependent who is also the head
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        is_tax_unit_dependent: false
+      person2:
+        age: 40
+        social_security_retirement: 60_000
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2]
+    marital_units:
+      marital_unit1:
+        members: [person1]
+      marital_unit2:
+        members: [person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # Every adult in tax_unit2 is input as a dependent, so person2 is also
+    # its head. Neither irs_gross_income (dependents) nor
+    # dependent_gross_income (heads) counts their taxable benefits, so none
+    # may be subtracted: § 15-30-2337(9)(a)(viii) counts all 60_000.
+    is_tax_unit_head: [true, true]
+    is_tax_unit_dependent: [false, true]
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 60_000]
+
+- name: A business loss on another household member's return does not reduce gross household income
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+      person2:
+        age: 40
+        taxable_interest_income: 10_000
+        self_employment_income: -5_000
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # The member's federal AGI is 10_000 - 5_000 = 5_000; the 5_000 loss is
+    # added back on their own return's head. 2024 Schedule 2EC line 10:
+    # "Do not include any losses generated from the business."
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
+
+- name: A dependent in another household member's tax unit counts
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 15_000
+      person2:
+        age: 35
+        employment_income: 25_000
+      person3:
+        age: 5
+      person4:
+        age: 8
+        employment_income: 3_000
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2, person3, person4]
+    households:
+      household:
+        members: [person1, person2, person3, person4]
+        state_name: MT
+  output:
+    # Three generations. The daughter's line 8 credits: federal EITC with
+    # two children 6_960 - 21.06% x (25_000 - 22_720) = 6_479.83; refundable
+    # child tax credit min(2 x 1_700, 15% x (25_000 - 2_500)) = 3_375;
+    # Montana EITC 10% = 647.98. Her total: 25_000 + 6_479.83 + 3_375 +
+    # 647.98 = 35_502.81. The grandchild is her dependent; their 3_000 of
+    # wages count through the dependent path.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [15_000, 35_502.81, 0, 3_000]

From 5c9ac0570e58a1347539ad417a9ca3af9a201b52 Mon Sep 17 00:00:00 2001
From: Max Ghenis <max@policyengine.org>
Date: Mon, 12 Oct 2026 06:24:43 -0400
Subject: [PATCH 3/6] Restore the year's gain hidden by a capital loss
 carryover in Montana elderly credit income

long_term_capital_gains already includes the prior-year long-term capital
loss carryover as a loss (Schedule D line 15; long_term_capital_loss_carryover
is a memo). A carryover is a loss, so it must not reduce gross household
income (MCA 15-30-2337(9)(a); 2024 Schedule 2EC line 7, "do not include any
capital losses"). Add it back to get the year's own long-term gain, as
az_property_tax_credit_capital_gains does, and restore only the gain it hid,
on both income paths. Restoration applies where an income path counts the
person, so a person input as both a dependent and the head stays excluded
from both, as before.

New cases: a carryover smaller than, larger than and equal to the year's
gain; a dependent's carryover; a long-term loss netted against a short-term
gain; losses exceeding the gain; and Social Security for a spouse also input
as a dependent. Review finding P2 (GPT-6.1 Sol) on #10139.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 ...mt_elderly_homeowner_or_renter_credit.yaml |  24 +++
 ..._renter_credit_gross_household_income.yaml | 162 ++++++++++++++++++
 ...or_renter_credit_gross_household_income.py |  45 +++--
 3 files changed, 219 insertions(+), 12 deletions(-)

diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
index 0891f65af24..32639b69686 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
@@ -665,3 +665,27 @@
     # minor's wages twice would give 40_000, line 22 = 1_370 and a credit of
     # (2_000 - 1_370) x 30% = 189.
     mt_elderly_homeowner_or_renter_credit: [1_130, 0]
+
+- name: 2024 Schedule 2EC, a capital loss carryover does not raise the credit
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: 6_000
+        long_term_capital_loss_carryover: 4_000
+        real_estate_taxes: 2_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # Line 5 = 20_000; line 7 = the year's 10_000 gain; line 18 = 30_000;
+    # line 22 = 870; line 30 = 1_130. Counting the 6_000 net would give line
+    # 18 = 26_000, line 22 = 670 and the 1_150 cap.
+    mt_elderly_homeowner_or_renter_credit: 1_130
diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
index 502bfc29e52..f318c2f1dc3 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
@@ -509,3 +509,165 @@
     # 647.98 = 35_502.81. The grandchild is her dependent; their 3_000 of
     # wages count through the dependent path.
     mt_elderly_homeowner_or_renter_credit_gross_household_income: [15_000, 35_502.81, 0, 3_000]
+
+- name: A prior-year capital loss carryover does not reduce the year's gain
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        # A 10_000 gain this year less a 4_000 carryover (Schedule D line 15).
+        long_term_capital_gains: 6_000
+        long_term_capital_loss_carryover: 4_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # Line 7 counts the year's gain, 10_000, without the carried loss.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 30_000
+
+- name: A carryover larger than the year's gain leaves the gain counted and the rest unused
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        # A 2_000 gain this year less a 10_000 carryover.
+        long_term_capital_gains: -8_000
+        long_term_capital_loss_carryover: 10_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # 20_000 + the year's 2_000 gain; the unused 8_000 of carryover counts
+    # neither as income nor as a loss.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 22_000
+
+- name: A carryover with no gain this year adds nothing
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: -5_000
+        long_term_capital_loss_carryover: 5_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 20_000
+
+- name: A dependent's capital loss carryover does not reduce their gain
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+      person2:
+        age: 16
+        long_term_capital_gains: 6_000
+        long_term_capital_loss_carryover: 4_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # Line 17: the dependent's 10_000 gain this year, as on a filer's return.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
+
+- name: A long-term loss netted against a short-term gain does not reduce gross household income
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: -4_000
+        short_term_capital_gains: 10_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 30_000
+
+- name: A gain is counted when the person's capital losses exceed it
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: -10_000
+        short_term_capital_gains: 4_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # Federal AGI 20_000 - 3_000 (the § 1211(b) limit); the 3_000 is added
+    # back and the 4_000 short-term gain counts: 24_000.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 24_000
+
+- name: Social Security counts in full for a spouse who is also input as a dependent
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        is_tax_unit_dependent: false
+      person2:
+        age: 50
+        social_security_retirement: 60_000
+        is_tax_unit_dependent: true
+      person3:
+        age: 45
+        social_security_retirement: 60_000
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit1:
+        members: [person1]
+      tax_unit2:
+        members: [person2, person3]
+    marital_units:
+      marital_unit1:
+        members: [person1]
+      marital_unit2:
+        members: [person2, person3]
+    households:
+      household:
+        members: [person1, person2, person3]
+        state_name: MT
+  output:
+    # Both adults of tax_unit2 are input as dependents, so they stay head and
+    # spouse as well. § 15-30-2337(9)(a)(viii) counts all of each one's
+    # benefits.
+    is_tax_unit_head: [true, true, false]
+    is_tax_unit_spouse: [false, false, true]
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 60_000, 60_000]
diff --git a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
index 1f10e5273a5..a7ebc1c990b 100644
--- a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
+++ b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
@@ -74,24 +74,45 @@ def formula(person, period, parameters):
         # losses."). The return's losses are added once, to the head.
         head = person("is_tax_unit_head", period)
         losses = head * person.tax_unit("loss_ald", period)
-        # loss_ald holds only the capital loss deducted in AGI. A filer's
-        # short-term loss netted against their own long-term gain (or the
-        # reverse) never reaches it, so restore that loss here: count each
-        # gain without its losses, as the dependent path does and as 2024
-        # Schedule 2EC line 7 requires ("do not include any capital
-        # losses"). Taking the larger of the floored parts and the net keeps
-        # a capital_gains value supplied directly as an input.
-        long_term_gains = max_(0, person("long_term_capital_gains", period))
+        # Count each person's capital gains without losses, as 2024 Schedule
+        # 2EC line 7 requires ("do not include any capital losses"). Two
+        # losses reduce the gains the income paths count without reaching
+        # loss_ald, which holds only the capital loss deducted in AGI:
+        # - a short-term loss netted against the same person's long-term gain
+        #   (or the reverse) inside capital_gains;
+        # - the prior-year long-term capital loss carryover, which
+        #   long_term_capital_gains already includes as a loss, as Schedule D
+        #   line 15 does. Adding it back gives the year's own long-term gain
+        #   (as az_property_tax_credit_capital_gains does); only the gain it
+        #   hid is restored, never the unused loss.
+        # Taking the larger of the floored parts and the net keeps a
+        # capital_gains value supplied directly as an input.
+        carryover = max_(0, person("long_term_capital_loss_carryover", period))
+        long_term_gains = max_(0, person("long_term_capital_gains", period) + carryover)
         short_term_gains = max_(0, person("short_term_capital_gains", period))
         capital_gains = person("capital_gains", period)
-        gains_without_losses = max_(long_term_gains + short_term_gains, capital_gains)
-        netted_capital_loss = ~is_dependent * (
-            gains_without_losses - max_(0, capital_gains)
+        gains_without_losses = max_(
+            long_term_gains + short_term_gains, capital_gains + carryover
         )
+        # The gains each income path already counted: irs_gross_income
+        # floors the net, dependent_gross_income floors each part. A person
+        # input as both a dependent and the head is counted by neither path,
+        # so nothing is restored for them.
+        counted_gains = where(
+            is_dependent,
+            ~head_or_spouse
+            * max_(
+                max_(0, person("long_term_capital_gains", period)) + short_term_gains,
+                capital_gains,
+            ),
+            max_(0, capital_gains),
+        )
+        counted_by_a_path = ~(is_dependent & head_or_spouse)
+        lost_capital_gains = counted_by_a_path * (gains_without_losses - counted_gains)
         return (
             sources
             + dependent_income
             + untaxed_social_security
             + losses
-            + netted_capital_loss
+            + lost_capital_gains
         )

From 737f3facfdccb33143378725b3dfbec36e047e9a Mon Sep 17 00:00:00 2001
From: Max Ghenis <max@policyengine.org>
Date: Mon, 12 Oct 2026 06:24:56 -0400
Subject: [PATCH 4/6] Describe the carryover in the changelog fragment

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md b/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md
index 4a3ddef2131..6ea58342f76 100644
--- a/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md
+++ b/changelog.d/fix-mt-ehrc-filer-gains-ss-roles.fixed.md
@@ -1 +1 @@
-Montana's elderly homeowner/renter credit now counts a filer's capital gains without the losses netted against them on the same return, and counts Social Security once when a person is input as both a tax unit dependent and the head.
+Montana's elderly homeowner/renter credit now counts each person's capital gains without losses netted on the same return or carried over from a prior year, and counts Social Security once when a person is input as both a tax unit dependent and the head or spouse.

From 2449fbd7845d2dab22aca077b5d0f730cfe220b1 Mon Sep 17 00:00:00 2001
From: Max Ghenis <max@policyengine.org>
Date: Mon, 12 Oct 2026 07:11:15 -0400
Subject: [PATCH 5/6] Count a carryover only against gains a direct net
 capital_gains input shows; add capital gains property tests

When capital_gains is supplied directly as a net amount, the long-term and
short-term parts default to zero, so adding the carryover to the long-term
part invented a gain: a direct -5,000 net with a 5,000 carryover counted
5,000 (review round 2 on #10139). Compute gains without losses as the year's
net, max(0, capital_gains + carryover), plus the netting between the
year's long-term and short-term amounts, max(0, a) + max(0, b) - max(0, a + b).
With parts supplied this is the floored parts; with a direct net it is the
net alone.

test_mt_elderly_credit_capital_gains.py checks, for random long-term and
short-term amounts or a direct net, a carryover and distributions, that a
household member's gains count without losses whether they are a dependent,
file their own return or are the claimant, against a reference written from
Schedule 2EC line 7, and that the credit is the same either way. It is
derandomized (20 examples, 11 s of test time locally); a 300-example random
local run passed, and it fails on main and on the previous head.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 ...mt_elderly_homeowner_or_renter_credit.yaml |  23 ++
 ..._renter_credit_gross_household_income.yaml |  65 ++++++
 .../test_mt_elderly_credit_capital_gains.py   | 197 ++++++++++++++++++
 ...or_renter_credit_gross_household_income.py |  19 +-
 4 files changed, 298 insertions(+), 6 deletions(-)
 create mode 100644 policyengine_us/tests/test_mt_elderly_credit_capital_gains.py

diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
index 32639b69686..8b0b1484799 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
@@ -689,3 +689,26 @@
     # line 22 = 870; line 30 = 1_130. Counting the 6_000 net would give line
     # 18 = 26_000, line 22 = 670 and the 1_150 cap.
     mt_elderly_homeowner_or_renter_credit: 1_130
+
+- name: 2024 Schedule 2EC, a carryover against a net loss supplied directly adds no gain
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 30_000
+        capital_gains: -5_000
+        long_term_capital_loss_carryover: 5_000
+        real_estate_taxes: 2_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # Line 18 = 30_000; line 22 = 17_400 x 0.05 = 870; line 30 = 1_130.
+    # Counting the carryover as a gain would give 35_000 and 880 x 40% = 352.
+    mt_elderly_homeowner_or_renter_credit: 1_130
diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
index f318c2f1dc3..35c1732014b 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
@@ -671,3 +671,68 @@
     is_tax_unit_head: [true, true, false]
     is_tax_unit_spouse: [false, false, true]
     mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 60_000, 60_000]
+
+- name: A carryover with a net capital loss supplied directly counts no gain
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 30_000
+        # A net amount supplied directly, without long-term and short-term
+        # parts; with the 5_000 carryover added back, the year's net is zero.
+        capital_gains: -5_000
+        long_term_capital_loss_carryover: 5_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # Federal AGI 30_000 - 3_000 (§ 1211(b)); the 3_000 is added back. No
+    # gain this year, so line 7 is zero: 30_000.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 30_000
+
+- name: A carryover with a net capital gain supplied directly restores the year's gain
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        capital_gains: 6_000
+        long_term_capital_loss_carryover: 4_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # The year's net gain is 6_000 + 4_000 = 10_000: 30_000.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 30_000
+
+- name: A dependent's carryover with a net capital loss supplied directly counts no gain
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+      person2:
+        age: 16
+        employment_income: 10_000
+        capital_gains: -5_000
+        long_term_capital_loss_carryover: 5_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
diff --git a/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py b/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py
new file mode 100644
index 00000000000..a2d8710f180
--- /dev/null
+++ b/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py
@@ -0,0 +1,197 @@
+"""Property tests: capital gains in Montana elderly homeowner/renter credit
+income are counted without losses.
+
+MCA 15-30-2337(9)(a) defines income as "federal adjusted gross income,
+without regard to loss", and 2024 Schedule 2EC line 7 says "do not include
+any capital losses". A person's capital gains therefore enter gross household
+income as the year's gains without losses. Three losses can hide them:
+a short-term loss netted against a long-term gain (or the reverse), the
+prior-year long-term capital loss carryover that long_term_capital_gains
+already includes, and losses netted against capital gain distributions. The
+model counts the gains through three paths (federal AGI and the loss_ald
+add-back for filers; dependent_gross_income for tax unit dependents) and
+restores what each path nets away.
+
+For a claimant aged 62 or older with a pension, and one other household
+member whose capital gains are drawn either as long-term and short-term
+parts or as a net capital_gains amount supplied directly, with a carryover
+and distributions:
+
+1. Gross household income equals the pension plus the member's gains without
+   losses: max(0, long-term + carryover) + max(0, short-term) from the parts,
+   or max(0, net + carryover) from a direct net amount, plus distributions.
+   This holds whether the member is the claimant's dependent (A), files
+   their own return (B), or is the claimant's own gains on the claimant's
+   return (C, the claimant alone with the member's capital inputs).
+2. The claimant's credit is the same in A and B.
+
+The reference is written from the form, independently of the model. The
+model computes in single precision, so comparisons allow one cent or eight
+float32 spacings at the case's total, whichever is larger.
+"""
+
+import numpy as np
+import pytest
+
+from policyengine_us import Simulation
+
+YEAR = 2024
+PENSION = 20_000
+PROPERTY_TAX = 2_000
+TOLERANCE = 0.01
+
+
+def capital_inputs(c=None):
+    """Every capital input, set for every person: once capital_gains is an
+    input for some people in a simulation, the others get its default (zero),
+    not long_term_capital_gains + short_term_capital_gains. A direct net amount
+    has no long-term or short-term parts."""
+    c = c or dict(direct=True, net=0, carryover=0, distributions=0)
+    if c["direct"]:
+        long_term, short_term, net = 0, 0, c["net"]
+    else:
+        long_term, short_term = c["long_term"], c["short_term"]
+        net = long_term + short_term
+    return {
+        "long_term_capital_gains": {YEAR: long_term},
+        "short_term_capital_gains": {YEAR: short_term},
+        "capital_gains": {YEAR: net},
+        "long_term_capital_loss_carryover": {YEAR: c["carryover"]},
+        "non_sch_d_capital_gains": {YEAR: c["distributions"]},
+    }
+
+
+def build_situation(cases):
+    """Per case, three Montana households: (A) the member is the claimant's
+    dependent, (B) the member files their own return and (C) the claimant
+    alone, with the member's capital inputs on the claimant's return."""
+    people, tax_units, marital_units, households = {}, {}, {}, {}
+    for i, c in enumerate(cases):
+        for arrangement in "ABC":
+            key = f"{arrangement}{i}"
+            claimant = f"claimant_{key}"
+            people[claimant] = {
+                "age": {YEAR: 70},
+                "taxable_pension_income": {YEAR: PENSION},
+                "real_estate_taxes": {YEAR: PROPERTY_TAX},
+                "is_tax_unit_dependent": {YEAR: False},
+                **capital_inputs(),
+            }
+            marital_units[f"marital_unit_{key}"] = {"members": [claimant]}
+            if arrangement == "C":
+                people[claimant].update(capital_inputs(c))
+                tax_units[f"tax_unit_{key}"] = {"members": [claimant]}
+                households[f"household_{key}"] = {
+                    "members": [claimant],
+                    "state_code": {YEAR: "MT"},
+                }
+                continue
+            member = f"member_{key}"
+            # Set for everyone: an input for some people gives the others its
+            # default, not its formula.
+            people[member] = {
+                "age": {YEAR: 30},
+                "is_tax_unit_dependent": {YEAR: arrangement == "A"},
+                **capital_inputs(c),
+            }
+            marital_units[f"marital_unit_{key}_member"] = {"members": [member]}
+            if arrangement == "A":
+                tax_units[f"tax_unit_{key}"] = {"members": [claimant, member]}
+            else:
+                tax_units[f"tax_unit_{key}"] = {"members": [claimant]}
+                tax_units[f"tax_unit_{key}_member"] = {"members": [member]}
+            households[f"household_{key}"] = {
+                "members": [claimant, member],
+                "state_code": {YEAR: "MT"},
+            }
+    return {
+        "people": people,
+        "tax_units": tax_units,
+        "marital_units": marital_units,
+        "households": households,
+    }
+
+
+def gains_without_losses(c):
+    """Schedule 2EC line 7 (and line 17 for another member): the year's
+    capital gains without losses, plus distributions."""
+    if c["direct"]:
+        gains = max(0, c["net"] + c["carryover"])
+    else:
+        gains = max(0, c["long_term"] + c["carryover"]) + max(0, c["short_term"])
+    return gains + c["distributions"]
+
+
+def check(cases):
+    simulation = Simulation(situation=build_situation(cases))
+    income = np.asarray(
+        simulation.calculate(
+            "mt_elderly_homeowner_or_renter_credit_gross_household_income",
+            YEAR,
+            map_to="household",
+        )
+    ).reshape(len(cases), 3)
+    credit = np.asarray(
+        simulation.calculate(
+            "mt_elderly_homeowner_or_renter_credit", YEAR, map_to="household"
+        )
+    ).reshape(len(cases), 3)
+    for i, c in enumerate(cases):
+        expected = PENSION + gains_without_losses(c)
+        scale = PENSION + sum(
+            abs(c[k])
+            for k in ["long_term", "short_term", "net", "carryover", "distributions"]
+        )
+        tol = max(TOLERANCE, 8 * float(np.spacing(np.float32(scale))))
+        # 1. Every path counts the gains without losses.
+        assert income[i] == pytest.approx([expected] * 3, abs=tol), c
+        # 2. The credit does not depend on how the member files.
+        assert credit[i, 0] == pytest.approx(credit[i, 1], abs=tol), c
+    return income, credit
+
+
+def test_examples():
+    """A 10,000 long-term gain this year with a 4,000 carryover (6,000 net);
+    a 4,000 short-term loss against it; and a direct -5,000 net with a 5,000
+    carryover, which hides no gain."""
+    zero = dict(long_term=0, short_term=0, net=0, carryover=0, distributions=0)
+    cases = [
+        {**zero, "direct": False, "long_term": 6_000, "carryover": 4_000},
+        {**zero, "direct": False, "long_term": 10_000, "short_term": -4_000},
+        {**zero, "direct": True, "net": -5_000, "carryover": 5_000},
+    ]
+    income, credit = check(cases)
+    assert income[:, 0].tolist() == pytest.approx([30_000, 30_000, 20_000])
+    # (30_000 - 12_600) x 0.05 = 870 and 2_000 - 870 = 1_130; the third case
+    # has 20_000: (7_400 x 0.035 = 259), so the 1_150 cap.
+    assert credit[:, 0].tolist() == pytest.approx([1_130, 1_130, 1_150], abs=0.01)
+
+
+try:
+    import hypothesis
+    import hypothesis.strategies as st
+except ImportError:  # pragma: no cover
+    hypothesis = None
+
+if hypothesis is not None:
+    SLOW = [hypothesis.HealthCheck.too_slow]
+    SIGNED = st.integers(min_value=-30_000, max_value=30_000)
+    NONNEGATIVE = st.integers(min_value=0, max_value=20_000)
+
+    @st.composite
+    def case(draw):
+        return {
+            "direct": draw(st.booleans()),
+            "long_term": draw(st.one_of(st.just(0), SIGNED)),
+            "short_term": draw(st.one_of(st.just(0), SIGNED)),
+            "net": draw(st.one_of(st.just(0), SIGNED)),
+            "carryover": draw(st.one_of(st.just(0), NONNEGATIVE)),
+            "distributions": draw(st.one_of(st.just(0), NONNEGATIVE)),
+        }
+
+    @hypothesis.settings(
+        max_examples=20, deadline=None, derandomize=True, suppress_health_check=SLOW
+    )
+    @hypothesis.given(st.lists(case(), min_size=1, max_size=8))
+    def test_gains_without_losses(cases):
+        check(cases)
diff --git a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
index a7ebc1c990b..c6c0003337e 100644
--- a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
+++ b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
@@ -85,15 +85,22 @@ def formula(person, period, parameters):
         #   line 15 does. Adding it back gives the year's own long-term gain
         #   (as az_property_tax_credit_capital_gains does); only the gain it
         #   hid is restored, never the unused loss.
-        # Taking the larger of the floored parts and the net keeps a
-        # capital_gains value supplied directly as an input.
+        # The year's net gain is capital_gains plus the carryover. Netting
+        # between the year's long-term and short-term amounts adds
+        # max(0, a) + max(0, b) - max(0, a + b) on top of it. When the parts
+        # are supplied this leaves the floored parts. When capital_gains is
+        # supplied directly as a net amount, without parts, the netting term
+        # is zero, so the carryover is not counted as a gain the parts never
+        # showed.
         carryover = max_(0, person("long_term_capital_loss_carryover", period))
-        long_term_gains = max_(0, person("long_term_capital_gains", period) + carryover)
-        short_term_gains = max_(0, person("short_term_capital_gains", period))
+        long_term = person("long_term_capital_gains", period) + carryover
+        short_term = person("short_term_capital_gains", period)
+        short_term_gains = max_(0, short_term)
         capital_gains = person("capital_gains", period)
-        gains_without_losses = max_(
-            long_term_gains + short_term_gains, capital_gains + carryover
+        netted_between_terms = (
+            max_(0, long_term) + short_term_gains - max_(0, long_term + short_term)
         )
+        gains_without_losses = max_(0, capital_gains + carryover) + netted_between_terms
         # The gains each income path already counted: irs_gross_income
         # floors the net, dependent_gross_income floors each part. A person
         # input as both a dependent and the head is counted by neither path,

From ca9c11bc4181efff7d2d544dd21ea5344af9399d Mon Sep 17 00:00:00 2001
From: Max Ghenis <max@policyengine.org>
Date: Mon, 12 Oct 2026 08:14:44 -0400
Subject: [PATCH 6/6] Let the long-term and short-term parts decide Montana
 elderly credit gains; test every sign region in one simulation

Once capital_gains is an input for anyone in a simulation, everyone without
one holds its default of zero, not the sum of their parts. The previous
identity started from capital_gains, so a dependent with only a 10,000
long-term gain, beside a claimant whose capital_gains was supplied as 0,
counted nothing (review round 3 on #10139). The parts now decide the gains
whenever either is nonzero, max(0, long-term + carryover) + max(0,
short-term); without parts, capital_gains is a net supplied directly and
counts as max(0, net + carryover). The restoration replaces whatever the
income path counted, so an inconsistent capital_gains input yields to the
parts.

test_mt_elderly_credit_capital_gains.py now builds one simulation from a
grid covering every sign region of the long-term amount plus carryover, the
short-term amount and a direct net, with and without distributions, in three
input styles (parts with their net, parts with the net left to default, a
net alone) and three placements (dependent, own return, claimant). It
replaces 20 Hypothesis-built simulations: 3.1 s of test time locally, peak
footprint 1.25 GB against 1.24 GB for importing the model and building a
one-person simulation, so about 8 MB for the test itself. It fails on main
and on the previous two heads.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 ...mt_elderly_homeowner_or_renter_credit.yaml |  24 ++
 ..._renter_credit_gross_household_income.yaml |  46 +++
 .../test_mt_elderly_credit_capital_gains.py   | 273 ++++++++++--------
 ...or_renter_credit_gross_household_income.py |  37 ++-
 4 files changed, 241 insertions(+), 139 deletions(-)

diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
index 8b0b1484799..66476008e3e 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit.yaml
@@ -712,3 +712,27 @@
     # Line 18 = 30_000; line 22 = 17_400 x 0.05 = 870; line 30 = 1_130.
     # Counting the carryover as a gain would give 35_000 and 880 x 40% = 352.
     mt_elderly_homeowner_or_renter_credit: 1_130
+
+- name: 2024 Schedule 2EC, a dependent's gain counts when another person's capital_gains is supplied
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        capital_gains: 0
+        real_estate_taxes: 2_000
+      person2:
+        age: 16
+        long_term_capital_gains: 10_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # Line 18 = 20_000 + 10_000 = 30_000; line 22 = 870; line 30 = 1_130.
+    mt_elderly_homeowner_or_renter_credit: [1_130, 0]
diff --git a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
index 35c1732014b..88c8b004aa0 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/mt/tax/income/credits/elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.yaml
@@ -736,3 +736,49 @@
         state_name: MT
   output:
     mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
+
+- name: A dependent's long-term gain counts when another person's capital_gains is supplied
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        capital_gains: 0
+      person2:
+        age: 16
+        long_term_capital_gains: 10_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_name: MT
+  output:
+    # capital_gains is an input for person1, so person2 holds its default of
+    # zero rather than the sum of their parts. The parts decide: line 17
+    # counts the dependent's 10_000 gain.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: [20_000, 10_000]
+
+- name: The long-term and short-term parts decide the gains when capital_gains disagrees with them
+  period: 2024
+  input:
+    people:
+      person1:
+        age: 70
+        taxable_pension_income: 20_000
+        long_term_capital_gains: 10_000
+        short_term_capital_gains: -4_000
+        capital_gains: 20_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_name: MT
+  output:
+    # The parts show a 10_000 gain and a 4_000 loss; line 7 counts 10_000,
+    # not the inconsistent 20_000 net: 30_000.
+    mt_elderly_homeowner_or_renter_credit_gross_household_income: 30_000
diff --git a/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py b/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py
index a2d8710f180..2377af122f6 100644
--- a/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py
+++ b/policyengine_us/tests/test_mt_elderly_credit_capital_gains.py
@@ -1,35 +1,50 @@
-"""Property tests: capital gains in Montana elderly homeowner/renter credit
-income are counted without losses.
+"""Invariant tests: capital gains in Montana elderly homeowner/renter credit
+income are counted without losses, however they are supplied.
 
 MCA 15-30-2337(9)(a) defines income as "federal adjusted gross income,
 without regard to loss", and 2024 Schedule 2EC line 7 says "do not include
-any capital losses". A person's capital gains therefore enter gross household
-income as the year's gains without losses. Three losses can hide them:
-a short-term loss netted against a long-term gain (or the reverse), the
-prior-year long-term capital loss carryover that long_term_capital_gains
-already includes, and losses netted against capital gain distributions. The
-model counts the gains through three paths (federal AGI and the loss_ald
-add-back for filers; dependent_gross_income for tax unit dependents) and
+any capital losses". So a person's capital gains enter gross household income
+as the year's gains without losses. Three losses can hide them:
+- a short-term loss netted against a long-term gain, or the reverse;
+- the prior-year long-term capital loss carryover, which
+  long_term_capital_gains already includes;
+- losses netted against capital gain distributions.
+
+The model counts gains through federal AGI and the loss_ald add-back for
+filers, and through dependent_gross_income for tax unit dependents, and
 restores what each path nets away.
 
-For a claimant aged 62 or older with a pension, and one other household
-member whose capital gains are drawn either as long-term and short-term
-parts or as a net capital_gains amount supplied directly, with a carryover
-and distributions:
-
-1. Gross household income equals the pension plus the member's gains without
-   losses: max(0, long-term + carryover) + max(0, short-term) from the parts,
-   or max(0, net + carryover) from a direct net amount, plus distributions.
-   This holds whether the member is the claimant's dependent (A), files
-   their own return (B), or is the claimant's own gains on the claimant's
-   return (C, the claimant alone with the member's capital inputs).
+The gain is a piecewise-linear function of a few amounts. So instead of
+random draws, one vectorized simulation covers a grid that reaches every
+sign region of the long-term amount plus carryover, the short-term amount,
+and a net amount, with and without distributions. It supplies them in three
+styles:
+
+- parts: long-term and short-term amounts, with capital_gains set to their
+  sum;
+- sparse parts: long-term and short-term amounts with capital_gains omitted.
+  Because capital_gains is an input for other people in the same
+  simulation, these people hold its default of zero, not the sum of their
+  parts (review round 3 of #10139);
+- net: capital_gains alone, without parts.
+
+Each case appears three ways: (A) a household member who is the claimant's
+dependent, (B) a member who files their own return, and (C) the claimant
+themselves.
+
+1. Gross household income is the claimant's pension plus the gains without
+   losses plus distributions. The reference is written from Schedule 2EC
+   line 7, independently of the model: with parts,
+   max(0, long-term + carryover) + max(0, short-term); without them,
+   max(0, net + carryover).
 2. The claimant's credit is the same in A and B.
 
-The reference is written from the form, independently of the model. The
-model computes in single precision, so comparisons allow one cent or eight
-float32 spacings at the case's total, whichever is larger.
+The model computes in single precision, so comparisons allow one cent or
+eight float32 spacings at the case's total, whichever is larger.
 """
 
+import itertools
+
 import numpy as np
 import pytest
 
@@ -40,31 +55,52 @@
 PROPERTY_TAX = 2_000
 TOLERANCE = 0.01
 
+LONG_TERM = [-12_000, -3_000, 0, 4_000, 11_000]
+SHORT_TERM = [-7_000, 0, 2_000, 9_000]
+NET = [-9_000, -2_500, 0, 3_000, 14_000]
+CARRYOVER = [0, 2_500, 15_000]
+DISTRIBUTIONS = [0, 4_000]
+
+
+def grid():
+    cases = []
+    for style in ["parts", "sparse"]:
+        for lt, st, co, dist in itertools.product(
+            LONG_TERM, SHORT_TERM, CARRYOVER, DISTRIBUTIONS
+        ):
+            if lt == 0 and st == 0:
+                continue  # no parts: covered by the net style
+            cases.append(
+                dict(style=style, long_term=lt, short_term=st, net=lt + st)
+                | dict(carryover=co, distributions=dist)
+            )
+    for net, co, dist in itertools.product(NET, CARRYOVER, DISTRIBUTIONS):
+        cases.append(
+            dict(style="net", long_term=0, short_term=0, net=net)
+            | dict(carryover=co, distributions=dist)
+        )
+    return cases
 
-def capital_inputs(c=None):
-    """Every capital input, set for every person: once capital_gains is an
-    input for some people in a simulation, the others get its default (zero),
-    not long_term_capital_gains + short_term_capital_gains. A direct net amount
-    has no long-term or short-term parts."""
-    c = c or dict(direct=True, net=0, carryover=0, distributions=0)
-    if c["direct"]:
-        long_term, short_term, net = 0, 0, c["net"]
-    else:
-        long_term, short_term = c["long_term"], c["short_term"]
-        net = long_term + short_term
-    return {
-        "long_term_capital_gains": {YEAR: long_term},
-        "short_term_capital_gains": {YEAR: short_term},
-        "capital_gains": {YEAR: net},
+
+def capital_inputs(c):
+    inputs = {
         "long_term_capital_loss_carryover": {YEAR: c["carryover"]},
         "non_sch_d_capital_gains": {YEAR: c["distributions"]},
     }
+    if c["style"] != "net":
+        inputs["long_term_capital_gains"] = {YEAR: c["long_term"]}
+        inputs["short_term_capital_gains"] = {YEAR: c["short_term"]}
+    if c["style"] != "sparse":
+        inputs["capital_gains"] = {YEAR: c["net"]}
+    return inputs
+
+
+NO_CAPITAL = dict(style="parts", long_term=0, short_term=0, net=0) | dict(
+    carryover=0, distributions=0
+)
 
 
 def build_situation(cases):
-    """Per case, three Montana households: (A) the member is the claimant's
-    dependent, (B) the member files their own return and (C) the claimant
-    alone, with the member's capital inputs on the claimant's return."""
     people, tax_units, marital_units, households = {}, {}, {}, {}
     for i, c in enumerate(cases):
         for arrangement in "ABC":
@@ -74,34 +110,31 @@ def build_situation(cases):
                 "age": {YEAR: 70},
                 "taxable_pension_income": {YEAR: PENSION},
                 "real_estate_taxes": {YEAR: PROPERTY_TAX},
+                # Set for everyone: an input for some people gives the others
+                # its default, not its formula.
                 "is_tax_unit_dependent": {YEAR: False},
-                **capital_inputs(),
+                **capital_inputs(c if arrangement == "C" else NO_CAPITAL),
             }
             marital_units[f"marital_unit_{key}"] = {"members": [claimant]}
+            members = [claimant]
             if arrangement == "C":
-                people[claimant].update(capital_inputs(c))
                 tax_units[f"tax_unit_{key}"] = {"members": [claimant]}
-                households[f"household_{key}"] = {
-                    "members": [claimant],
-                    "state_code": {YEAR: "MT"},
-                }
-                continue
-            member = f"member_{key}"
-            # Set for everyone: an input for some people gives the others its
-            # default, not its formula.
-            people[member] = {
-                "age": {YEAR: 30},
-                "is_tax_unit_dependent": {YEAR: arrangement == "A"},
-                **capital_inputs(c),
-            }
-            marital_units[f"marital_unit_{key}_member"] = {"members": [member]}
-            if arrangement == "A":
-                tax_units[f"tax_unit_{key}"] = {"members": [claimant, member]}
             else:
-                tax_units[f"tax_unit_{key}"] = {"members": [claimant]}
-                tax_units[f"tax_unit_{key}_member"] = {"members": [member]}
+                member = f"member_{key}"
+                people[member] = {
+                    "age": {YEAR: 30},
+                    "is_tax_unit_dependent": {YEAR: arrangement == "A"},
+                    **capital_inputs(c),
+                }
+                marital_units[f"marital_unit_{key}_member"] = {"members": [member]}
+                members.append(member)
+                if arrangement == "A":
+                    tax_units[f"tax_unit_{key}"] = {"members": members}
+                else:
+                    tax_units[f"tax_unit_{key}"] = {"members": [claimant]}
+                    tax_units[f"tax_unit_{key}_member"] = {"members": [member]}
             households[f"household_{key}"] = {
-                "members": [claimant, member],
+                "members": members,
                 "state_code": {YEAR: "MT"},
             }
     return {
@@ -113,85 +146,77 @@ def build_situation(cases):
 
 
 def gains_without_losses(c):
-    """Schedule 2EC line 7 (and line 17 for another member): the year's
-    capital gains without losses, plus distributions."""
-    if c["direct"]:
+    """Schedule 2EC line 7 (line 17 for another member) plus distributions."""
+    if c["style"] == "net":
         gains = max(0, c["net"] + c["carryover"])
     else:
         gains = max(0, c["long_term"] + c["carryover"]) + max(0, c["short_term"])
     return gains + c["distributions"]
 
 
-def check(cases):
+@pytest.fixture(scope="module")
+def results():
+    cases = grid()
     simulation = Simulation(situation=build_situation(cases))
+    shape = (len(cases), 3)
     income = np.asarray(
         simulation.calculate(
             "mt_elderly_homeowner_or_renter_credit_gross_household_income",
             YEAR,
             map_to="household",
         )
-    ).reshape(len(cases), 3)
+    ).reshape(shape)
     credit = np.asarray(
         simulation.calculate(
             "mt_elderly_homeowner_or_renter_credit", YEAR, map_to="household"
         )
-    ).reshape(len(cases), 3)
+    ).reshape(shape)
+    return cases, income, credit
+
+
+def tolerance(c):
+    scale = PENSION + sum(
+        abs(c[k]) for k in ["long_term", "short_term", "net", "carryover"]
+    )
+    scale += c["distributions"]
+    return max(TOLERANCE, 8 * float(np.spacing(np.float32(scale))))
+
+
+def test_gains_count_without_losses_on_every_path(results):
+    cases, income, _ = results
     for i, c in enumerate(cases):
         expected = PENSION + gains_without_losses(c)
-        scale = PENSION + sum(
-            abs(c[k])
-            for k in ["long_term", "short_term", "net", "carryover", "distributions"]
-        )
-        tol = max(TOLERANCE, 8 * float(np.spacing(np.float32(scale))))
-        # 1. Every path counts the gains without losses.
-        assert income[i] == pytest.approx([expected] * 3, abs=tol), c
-        # 2. The credit does not depend on how the member files.
-        assert credit[i, 0] == pytest.approx(credit[i, 1], abs=tol), c
-    return income, credit
-
-
-def test_examples():
-    """A 10,000 long-term gain this year with a 4,000 carryover (6,000 net);
-    a 4,000 short-term loss against it; and a direct -5,000 net with a 5,000
-    carryover, which hides no gain."""
-    zero = dict(long_term=0, short_term=0, net=0, carryover=0, distributions=0)
-    cases = [
-        {**zero, "direct": False, "long_term": 6_000, "carryover": 4_000},
-        {**zero, "direct": False, "long_term": 10_000, "short_term": -4_000},
-        {**zero, "direct": True, "net": -5_000, "carryover": 5_000},
-    ]
-    income, credit = check(cases)
-    assert income[:, 0].tolist() == pytest.approx([30_000, 30_000, 20_000])
-    # (30_000 - 12_600) x 0.05 = 870 and 2_000 - 870 = 1_130; the third case
-    # has 20_000: (7_400 x 0.035 = 259), so the 1_150 cap.
-    assert credit[:, 0].tolist() == pytest.approx([1_130, 1_130, 1_150], abs=0.01)
-
-
-try:
-    import hypothesis
-    import hypothesis.strategies as st
-except ImportError:  # pragma: no cover
-    hypothesis = None
-
-if hypothesis is not None:
-    SLOW = [hypothesis.HealthCheck.too_slow]
-    SIGNED = st.integers(min_value=-30_000, max_value=30_000)
-    NONNEGATIVE = st.integers(min_value=0, max_value=20_000)
-
-    @st.composite
-    def case(draw):
-        return {
-            "direct": draw(st.booleans()),
-            "long_term": draw(st.one_of(st.just(0), SIGNED)),
-            "short_term": draw(st.one_of(st.just(0), SIGNED)),
-            "net": draw(st.one_of(st.just(0), SIGNED)),
-            "carryover": draw(st.one_of(st.just(0), NONNEGATIVE)),
-            "distributions": draw(st.one_of(st.just(0), NONNEGATIVE)),
-        }
-
-    @hypothesis.settings(
-        max_examples=20, deadline=None, derandomize=True, suppress_health_check=SLOW
+        assert income[i] == pytest.approx([expected] * 3, abs=tolerance(c)), c
+
+
+def test_credit_does_not_depend_on_how_the_member_files(results):
+    cases, _, credit = results
+    for i, c in enumerate(cases):
+        assert credit[i, 0] == pytest.approx(credit[i, 1], abs=tolerance(c)), c
+
+
+def test_hand_checked_cases(results):
+    """Two grid cases are checked by hand. A long-term amount of 11,000 that
+    already nets a 15,000 carryover, with a 9,000 short-term gain and no net
+    supplied (sparse): the year's long-term gain is 26,000, so 20,000 +
+    26,000 + 9,000 = 55,000, and the credit is 0 (55,000 is at least
+    45,000). A net -2,500 supplied
+    directly with a 2,500 carryover: no gain, so 20,000; (20,000 - 12,600) x
+    0.035 = 259, and min(2,000 - 259, 1,150) = 1,150."""
+    cases, income, credit = results
+
+    def find(**kw):
+        return next(i for i, c in enumerate(cases) if kw.items() <= c.items())
+
+    i = find(
+        style="sparse",
+        long_term=11_000,
+        short_term=9_000,
+        carryover=15_000,
+        distributions=0,
     )
-    @hypothesis.given(st.lists(case(), min_size=1, max_size=8))
-    def test_gains_without_losses(cases):
-        check(cases)
+    assert income[i].tolist() == pytest.approx([55_000] * 3)
+    assert credit[i].tolist() == pytest.approx([0] * 3)
+    j = find(style="net", net=-2_500, carryover=2_500, distributions=0)
+    assert income[j].tolist() == pytest.approx([20_000] * 3)
+    assert credit[j].tolist() == pytest.approx([1_150] * 3, abs=0.01)
diff --git a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
index c6c0003337e..4f6ba36ed86 100644
--- a/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
+++ b/policyengine_us/variables/gov/states/mt/tax/income/credits/mt_elderly_homeowner_or_renter/mt_elderly_homeowner_or_renter_credit_gross_household_income.py
@@ -85,31 +85,38 @@ def formula(person, period, parameters):
         #   line 15 does. Adding it back gives the year's own long-term gain
         #   (as az_property_tax_credit_capital_gains does); only the gain it
         #   hid is restored, never the unused loss.
-        # The year's net gain is capital_gains plus the carryover. Netting
-        # between the year's long-term and short-term amounts adds
-        # max(0, a) + max(0, b) - max(0, a + b) on top of it. When the parts
-        # are supplied this leaves the floored parts. When capital_gains is
-        # supplied directly as a net amount, without parts, the netting term
-        # is zero, so the carryover is not counted as a gain the parts never
-        # showed.
+        # The long-term and short-term parts, when either is nonzero, decide
+        # the gains: max(0, long-term + carryover) + max(0, short-term).
+        # capital_gains can disagree with them: once it is an input for
+        # anyone in a simulation, everyone without one holds its default of
+        # zero, not the sum of their parts. Without parts, capital_gains is a
+        # net amount supplied directly, and the gain is max(0, net +
+        # carryover); the carryover is never counted as a gain the parts did
+        # not show.
         carryover = max_(0, person("long_term_capital_loss_carryover", period))
-        long_term = person("long_term_capital_gains", period) + carryover
-        short_term = person("short_term_capital_gains", period)
-        short_term_gains = max_(0, short_term)
+        long_term_capital_gains = person("long_term_capital_gains", period)
+        short_term_capital_gains = person("short_term_capital_gains", period)
+        short_term_gains = max_(0, short_term_capital_gains)
         capital_gains = person("capital_gains", period)
-        netted_between_terms = (
-            max_(0, long_term) + short_term_gains - max_(0, long_term + short_term)
+        parts_supplied = (long_term_capital_gains != 0) | (
+            short_term_capital_gains != 0
+        )
+        gains_without_losses = where(
+            parts_supplied,
+            max_(0, long_term_capital_gains + carryover) + short_term_gains,
+            max_(0, capital_gains + carryover),
         )
-        gains_without_losses = max_(0, capital_gains + carryover) + netted_between_terms
         # The gains each income path already counted: irs_gross_income
-        # floors the net, dependent_gross_income floors each part. A person
+        # floors the net, dependent_gross_income floors each part. The
+        # difference replaces them with the gains above; it is negative only
+        # when an inconsistent capital_gains input exceeds the parts. A person
         # input as both a dependent and the head is counted by neither path,
         # so nothing is restored for them.
         counted_gains = where(
             is_dependent,
             ~head_or_spouse
             * max_(
-                max_(0, person("long_term_capital_gains", period)) + short_term_gains,
+                max_(0, long_term_capital_gains) + short_term_gains,
                 capital_gains,
             ),
             max_(0, capital_gains),