diff --git a/changelog.d/student-loan-interest-claimed-spouse.fixed.md b/changelog.d/student-loan-interest-claimed-spouse.fixed.md
new file mode 100644
index 00000000000..5790737c6cc
--- /dev/null
+++ b/changelog.d/student-loan-interest-claimed-spouse.fixed.md
@@ -0,0 +1 @@
+Let the unclaimed spouse on a joint return deduct their own student loan interest when the other spouse is claimed as a dependent elsewhere (26 U.S.C. 221(c)), and count both spouses in joint MAGI.
diff --git a/policyengine_us/tests/core/test_ald_determinism.py b/policyengine_us/tests/core/test_ald_determinism.py
index 4dd95f6dd2c..4196b389ea8 100644
--- a/policyengine_us/tests/core/test_ald_determinism.py
+++ b/policyengine_us/tests/core/test_ald_determinism.py
@@ -38,6 +38,7 @@
     "alimony_expense_ald": 1,
     "health_savings_account_ald": 1,
     "student_loan_interest_ald_eligible": True,
+    "is_tax_unit_head_or_spouse": True,
     "is_tax_unit_dependent": False,
     "is_tax_unit_head": True,
     "is_tax_unit_spouse": False,
diff --git a/policyengine_us/tests/core/test_student_loan_interest_claimed_spouse_invariants.py b/policyengine_us/tests/core/test_student_loan_interest_claimed_spouse_invariants.py
new file mode 100644
index 00000000000..46300826ea6
--- /dev/null
+++ b/policyengine_us/tests/core/test_student_loan_interest_claimed_spouse_invariants.py
@@ -0,0 +1,193 @@
+"""Student loan interest deduction on a joint return with a claimed spouse.
+
+IRC 221(c) denies the deduction "to an individual" for whom another taxpayer
+is allowed a dependency deduction. The bar reaches that individual only: on a
+joint return the unclaimed spouse keeps the deduction for their own interest,
+under the single return-level cap of IRC 221(b)(1) and the joint phase-out of
+IRC 221(b)(2), whose MAGI includes both spouses.
+
+Hypothesis draws batches of joint couples with one unclaimed filer and one
+filer who may be claimed. Each couple draws whether the claimable filer is the
+head or the spouse, so the checks hold for either claimed filer. Each couple
+runs in one vectorized simulation in four variants:
+
+- A: the claimable filer is claimed and has the drawn interest;
+- B: the claimable filer is claimed and has no interest;
+- C: the claimable filer is not claimed and has no interest;
+- D: the claimable filer is not claimed and has the drawn interest.
+
+The checks:
+
+1. The unclaimed filer's deduction is the same in A, B and C: it never
+   depends on the claimed filer's own interest, or on whether a filer with no
+   interest is claimed.
+2. A claimed filer's own interest is never deducted: their deduction is zero
+   and the return's total in A is no more than the unclaimed filer's own
+   interest.
+3. The return's deduction never exceeds the cap, in every variant.
+
+Explicit examples put a claimed filer's income inside the joint phase-out in
+both years, with the claimed filer as head and as spouse, so a joint MAGI that
+dropped the claimed filer would break check 1 by hundreds of dollars.
+"""
+
+import numpy as np
+from hypothesis import HealthCheck, example, given, settings
+from hypothesis import strategies as st
+
+from policyengine_us import Simulation
+
+TOLERANCE = 0.01
+VARIANTS = {
+    "A": dict(claimed=True, spouse_interest=True),
+    "B": dict(claimed=True, spouse_interest=False),
+    "C": dict(claimed=False, spouse_interest=False),
+    "D": dict(claimed=False, spouse_interest=True),
+}
+
+money = st.integers(0, 200_000).map(float)
+interest = st.one_of(st.just(0.0), st.integers(1, 4_000).map(float))
+
+
+@st.composite
+def couples(draw):
+    return {
+        "claimed_role": draw(st.sampled_from(["spouse", "head"])),
+        "unclaimed_income": draw(money),
+        "claimed_income": draw(st.one_of(st.just(0.0), money)),
+        "unclaimed_interest": draw(interest),
+        "claimed_interest": draw(interest),
+    }
+
+
+def couple(
+    claimed_role,
+    unclaimed_income,
+    claimed_income,
+    unclaimed_interest,
+    claimed_interest,
+):
+    return dict(
+        claimed_role=claimed_role,
+        unclaimed_income=float(unclaimed_income),
+        claimed_income=float(claimed_income),
+        unclaimed_interest=float(unclaimed_interest),
+        claimed_interest=float(claimed_interest),
+    )
+
+
+# Couples whose claimed filer's income moves the joint phase-out. 2025: start
+# $170,000, range $30,000; 2019: start $140,000, range $30,000.
+PHASE_OUT_2025 = [
+    # Joint MAGI 150,000 + 30,000 = 180,000: 2,500 x (1 - 10/30) = 1,666.67,
+    # against 2,500 if the claimed spouse's 30,000 were dropped.
+    couple("spouse", 150_000, 30_000, 2_500, 1_000),
+    # The same with the head claimed.
+    couple("head", 150_000, 30_000, 2_500, 1_000),
+    # Joint MAGI 165,000 + 20,000 = 185,000: 2,000 x (1 - 15/30) = 1,000,
+    # against 2,000 x (1 - 0) = 2,000 at 165,000.
+    couple("spouse", 165_000, 20_000, 2_000, 3_000),
+    couple("spouse", 2_000, 0, 1_000, 700),
+]
+PHASE_OUT_2019 = [
+    # Joint MAGI 130,000 + 20,000 = 150,000: 2,000 x (1 - 10/30) = 1,333.33,
+    # against 2,000 at 130,000.
+    couple("spouse", 130_000, 20_000, 2_000, 500),
+    couple("head", 130_000, 20_000, 2_000, 500),
+    couple("head", 0, 0, 0, 0),
+]
+
+
+def _situation(units, year):
+    people, tax_units, households = {}, {}, {}
+    for i, unit in enumerate(units):
+        claimed_is_head = unit["claimed_role"] == "head"
+        for key, variant in VARIANTS.items():
+            unclaimed, claimed = f"unclaimed_{i}_{key}", f"claimed_{i}_{key}"
+            people[unclaimed] = {
+                "age": {year: 30},
+                "employment_income": {year: unit["unclaimed_income"]},
+                "student_loan_interest": {year: unit["unclaimed_interest"]},
+                "claimed_as_dependent_on_another_return": {year: False},
+                "is_tax_unit_head": {year: not claimed_is_head},
+                "is_tax_unit_spouse": {year: claimed_is_head},
+            }
+            claimed_interest = (
+                unit["claimed_interest"] if variant["spouse_interest"] else 0.0
+            )
+            people[claimed] = {
+                "age": {year: 22},
+                "employment_income": {year: unit["claimed_income"]},
+                "student_loan_interest": {year: claimed_interest},
+                "claimed_as_dependent_on_another_return": {year: variant["claimed"]},
+                "is_tax_unit_head": {year: claimed_is_head},
+                "is_tax_unit_spouse": {year: not claimed_is_head},
+            }
+            members = [unclaimed, claimed]
+            tax_units[f"tu_{i}_{key}"] = {
+                "members": members,
+                "filing_status": {year: "JOINT"},
+            }
+            households[f"hh_{i}_{key}"] = {
+                "members": members,
+                "state_code": {year: "TX"},
+            }
+    return {"people": people, "tax_units": tax_units, "households": households}
+
+
+def _check(units, year):
+    sim = Simulation(situation=_situation(units, year))
+    ald = sim.calculate("student_loan_interest_ald", year)
+    own = sim.calculate("student_loan_interest", year)
+    cap = sim.tax_benefit_system.parameters(
+        f"{year}-01-01"
+    ).gov.irs.ald.student_loan_interest.cap.JOINT
+    n_variants = len(VARIANTS)
+    # People are ordered unit by unit, variant by variant, unclaimed filer
+    # then claimable filer, whichever of them is the head.
+    ald = ald.reshape(len(units), n_variants, 2)
+    own = own.reshape(len(units), n_variants, 2)
+    a, b, c, d = range(n_variants)
+    unclaimed_ald = ald[:, :, 0]
+
+    # 1. The unclaimed filer's deduction ignores the claimed filer.
+    np.testing.assert_allclose(unclaimed_ald[:, a], unclaimed_ald[:, b], atol=TOLERANCE)
+    np.testing.assert_allclose(unclaimed_ald[:, a], unclaimed_ald[:, c], atol=TOLERANCE)
+
+    # 2. The claimed filer's own interest is never deducted.
+    assert (ald[:, [a, b], 1] == 0).all()
+    assert (ald[:, a].sum(axis=1) <= own[:, a, 0] + TOLERANCE).all()
+
+    # 3. The return's deduction never exceeds the cap.
+    assert (ald.sum(axis=2) <= cap + TOLERANCE).all()
+    assert (ald >= 0).all()
+    # The claimed filer doesn't change the unclaimed filer's deduction
+    # through the shared cap: with the claimable filer's interest, the
+    # unclaimed filer's share in D is never above their deduction in A.
+    assert (unclaimed_ald[:, d] <= unclaimed_ald[:, a] + TOLERANCE).all()
+
+
+SETTINGS = dict(
+    max_examples=4,
+    deadline=None,
+    derandomize=True,
+    suppress_health_check=[HealthCheck.too_slow, HealthCheck.data_too_large],
+)
+
+
+@settings(**SETTINGS)
+@example(PHASE_OUT_2025, 2025)
+@example(PHASE_OUT_2019, 2019)
+@given(st.lists(couples(), min_size=10, max_size=30), st.sampled_from([2019, 2025]))
+def test_claimed_spouse_invariants(units, year):
+    _check(units, year)
+
+
+def test_crafted_witnesses():
+    # A claimed spouse with interest beside an unclaimed head below and in
+    # the 2025 joint phase-out ($170,000 start, $30,000 range).
+    units = [
+        couple("spouse", 2_000, 0, 1_000, 700),
+        couple("spouse", 150_000, 30_000, 4_000, 3_000),
+    ]
+    _check(units, 2025)
diff --git a/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald.yaml b/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald.yaml
index 717160aaf00..dc624c3781b 100644
--- a/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald.yaml
@@ -259,3 +259,107 @@
   output:
     # MAGI 70,000 + 15,000 = 85,000; reduced by (85,000 - 80,000) / 15,000.
     student_loan_interest_ald: 1_666.67
+
+# IRC 221(c) denies the deduction "to an individual" whom another taxpayer
+# claims. On a joint return filed only to claim a refund (IRC 152(c)(1)(E)),
+# the unclaimed spouse keeps the deduction for their own interest.
+- name: Unclaimed spouse retains own loan-interest deduction on a refund-only joint return
+  period: 2025
+  input:
+    people:
+      unclaimed:
+        age: 30
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+        employment_income: 2_000
+        student_loan_interest: 1_000
+      claimed_student:
+        age: 22
+        is_full_time_student: true
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+        claimable_as_dependent_on_another_return: true
+        claimed_as_dependent_on_another_return: true
+        student_loan_interest: 700
+    tax_units:
+      joint:
+        members: [unclaimed, claimed_student]
+        filing_status: JOINT
+    households:
+      household:
+        members: [unclaimed, claimed_student]
+        state_code: TX
+  output:
+    # Eligible interest 1,000 + 0; the 2,500 cap and the 170,000 phase-out
+    # start don't bind. AGI = 2,000 - 1,000.
+    student_loan_interest_ald_eligible: [true, false]
+    student_loan_interest_ald: [1_000, 0]
+    adjusted_gross_income: 1_000
+
+- name: Claimed head does not bar the unclaimed spouse or drop out of joint MAGI
+  period: 2025
+  input:
+    people:
+      claimed_student:
+        age: 22
+        is_full_time_student: true
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+        claimable_as_dependent_on_another_return: true
+        claimed_as_dependent_on_another_return: true
+        employment_income: 1_000
+        student_loan_interest: 700
+      unclaimed:
+        age: 30
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+        employment_income: 4_000
+        student_loan_interest: 4_000
+    tax_units:
+      joint:
+        members: [claimed_student, unclaimed]
+        filing_status: JOINT
+    households:
+      household:
+        members: [claimed_student, unclaimed]
+        state_code: TX
+  output:
+    # Eligible interest 4,000, capped once at 2,500. Joint MAGI
+    # 1,000 + 4,000 = 5,000. AGI = 5,000 - 2,500.
+    student_loan_interest_ald_eligible: [false, true]
+    student_loan_interest_ald_magi: [1_000, 4_000]
+    student_loan_interest_ald: [0, 2_500]
+    adjusted_gross_income: 2_500
+
+# Mechanics only: the claim is set as an input. The joint phase-out reads
+# both spouses' MAGI (IRC 221(b)(2)(B)), including a claimed spouse's.
+- name: Joint phase-out counts the claimed spouse's MAGI
+  period: 2025
+  absolute_error_margin: 0.01
+  input:
+    people:
+      unclaimed:
+        age: 30
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+        employment_income: 150_000
+        student_loan_interest: 2_500
+      claimed_spouse:
+        age: 22
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+        claimed_as_dependent_on_another_return: true
+        employment_income: 30_000
+    tax_units:
+      joint:
+        members: [unclaimed, claimed_spouse]
+        filing_status: JOINT
+    households:
+      household:
+        members: [unclaimed, claimed_spouse]
+        state_code: TX
+  output:
+    # Joint MAGI 180,000; reduced by (180,000 - 170,000) / 30,000:
+    # 2,500 x (1 - 1/3) = 1,666.67.
+    student_loan_interest_ald_magi: [150_000, 30_000]
+    student_loan_interest_ald: [1_666.67, 0]
diff --git a/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald_eligible.yaml b/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald_eligible.yaml
index e161077097f..4241b0edb0c 100644
--- a/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald_eligible.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/student_loan_interest/student_loan_interest_ald_eligible.yaml
@@ -56,7 +56,7 @@
     # IRC 221(c).
     student_loan_interest_ald_eligible: false
 
-- name: 2024 joint return with one spouse claimed elsewhere cannot deduct student loan interest (the claimable spouse is the head)
+- name: 2024 joint return with the head claimed elsewhere; only the claimed head is barred
   period: 2024
   input:
     people:
@@ -78,11 +78,11 @@
         members: [person_a, person_b]
         state_code: TX
   output:
-    # Form 1040 instructions: "you, or your spouse if filing jointly, aren't
-    # claimed as a dependent".
-    student_loan_interest_ald_eligible: [false, false]
+    # IRC 221(c) bars the claimed individual only; the statute governs the
+    # Form 1040 instructions, which bar the whole joint return.
+    student_loan_interest_ald_eligible: [false, true]
 
-- name: 2024 joint return with one spouse claimed elsewhere cannot deduct student loan interest (the claimable spouse is the spouse)
+- name: 2024 joint return with the spouse claimed elsewhere; only the claimed spouse is barred
   period: 2024
   input:
     people:
@@ -104,7 +104,7 @@
         members: [person_b, person_a]
         state_code: TX
   output:
-    student_loan_interest_ald_eligible: [false, false]
+    student_loan_interest_ald_eligible: [true, false]
 
 # IRC 221(c): the bar applies to an individual who is claimed.
 - name: 2024 single filer who can be claimed but is not claimed can deduct student loan interest
diff --git a/policyengine_us/tests/policy/baseline/gov/states/hi/tax/income/hi_student_loan_interest_adjustment.yaml b/policyengine_us/tests/policy/baseline/gov/states/hi/tax/income/hi_student_loan_interest_adjustment.yaml
index a40d25ee3fd..682cd09349e 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/hi/tax/income/hi_student_loan_interest_adjustment.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/hi/tax/income/hi_student_loan_interest_adjustment.yaml
@@ -273,3 +273,44 @@
     hi_subtractions: 5_000
     # $62,500 + $1,666.67 addition - $5,000 pension subtraction.
     hi_agi: 59_166.67
+
+- name: Hawaii deduction keeps the unclaimed head's interest on a joint return with a claimed spouse
+  period: 2025
+  absolute_error_margin: 0.01
+  input:
+    people:
+      head:
+        age: 30
+        employment_income: 2_000
+        student_loan_interest: 1_000
+        is_tax_unit_head: true
+      spouse:
+        age: 22
+        is_full_time_student: true
+        is_tax_unit_spouse: true
+        claimable_as_dependent_on_another_return: true
+        claimed_as_dependent_on_another_return: true
+        student_loan_interest: 700
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+        filing_status: JOINT
+    spm_units:
+      spm_unit:
+        members: [head, spouse]
+    households:
+      household:
+        members: [head, spouse]
+        state_code: HI
+  output:
+    # IRC 221(c) bars only the claimed spouse, so Hawaii counts the head's
+    # interest only: min(1,000, 2,500 cap) = 1,000. Federal AGI is
+    # 2,000 - 1,000 = 1,000; Hawaii MAGI adds back the 1,000 federal
+    # deduction, giving 2,000, below the 100,000 joint phase-out start.
+    student_loan_interest_ald_eligible: [true, false]
+    hi_modified_agi: 2_000
+    hi_student_loan_interest_deduction: 1_000
+    # Hawaii deduction 1,000 - federal deduction 1,000 = 0, so Hawaii AGI
+    # equals federal AGI.
+    hi_student_loan_interest_adjustment: 0
+    hi_agi: 1_000
diff --git a/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/ky_federal_agi.yaml b/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/ky_federal_agi.yaml
index faebdf8b0fd..24d98364314 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/ky_federal_agi.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/ky_federal_agi.yaml
@@ -361,3 +361,41 @@
   output:
     adjusted_gross_income: 40_000
     ky_federal_agi: [0, 40_000]
+
+# IRC 221(c) bars only the claimed spouse from the student loan interest
+# deduction; Kentucky starts each column from the filer's own federal AGI.
+# Mechanics only: the claim is set as an input on a return that couldn't be
+# refund-only at this income.
+- name: Unclaimed head's student loan interest deduction lowers Kentucky AGI on a joint return with a claimed spouse
+  period: 2025
+  input:
+    people:
+      head:
+        age: 30
+        employment_income: 50_000
+        student_loan_interest: 2_000
+        is_tax_unit_head: true
+      spouse:
+        age: 22
+        is_tax_unit_spouse: true
+        claimed_as_dependent_on_another_return: true
+        student_loan_interest: 1_000
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+        filing_status: JOINT
+    households:
+      household:
+        members: [head, spouse]
+        state_code: KY
+  output:
+    # Federal: only the head's 2,000 is eligible; joint MAGI 50,000 is below
+    # the 170,000 phase-out start. Head AGI 50,000 - 2,000 = 48,000.
+    student_loan_interest_ald: [2_000, 0]
+    ky_federal_agi: [48_000, 0]
+    ky_agi: [48_000, 0]
+    # Joint: (48,000 - 3,270 standard deduction) x 4% = 1,789.20. The
+    # separate path gives the same (the spouse's column is 0), so the joint
+    # path stands. Family size credit: Kentucky modified AGI 48,000 is above
+    # its range for two; no personal or refundable credits apply.
+    ky_income_tax: 1_789.20
diff --git a/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_eligible.py b/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_eligible.py
index fd1bcc2bab0..ae5de35368c 100644
--- a/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_eligible.py
+++ b/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_eligible.py
@@ -6,11 +6,16 @@ class student_loan_interest_ald_eligible(Variable):
     entity = Person
     label = "Eligible for the Student loan interest ALD"
     definition_period = YEAR
-    reference = "https://www.law.cornell.edu/uscode/text/26/221"
+    reference = (
+        "https://www.law.cornell.edu/uscode/text/26/221#c",
+        "https://www.law.cornell.edu/uscode/text/26/221#e_2",
+    )
     documentation = (
         "Eligibility for the student loan interest above-the-line deduction. "
         "Per IRC § 221, the taxpayer must not file as Married Filing Separately "
-        "(§ 221(e)(2)) and cannot be claimed as a dependent (§ 221(c)). "
+        "(§ 221(e)(2)) and must not be an individual whom another taxpayer "
+        "claims as a dependent (§ 221(c)); on a joint return that bar "
+        "applies to the claimed spouse only. "
         "The MAGI phase-out is handled separately in the deduction calculation. "
         "Note: While § 221(d)(3) references § 25A(b)(3) for the definition of "
         "'eligible student', this refers to the student's status when the loan "
@@ -20,15 +25,14 @@ class student_loan_interest_ald_eligible(Variable):
 
     def formula(person, period, parameters):
         head_or_spouse = person("is_tax_unit_head_or_spouse", period)
-        # Per IRC § 221(c), no deduction for an individual for whom a section
-        # 151 deduction "is allowed to another taxpayer"; the Form 1040
-        # instructions require that "you, or your spouse if filing jointly,
-        # aren't claimed as a dependent", so either filer being claimed bars
-        # the return. This turns on an actual claim, so it reads the claimed
-        # input rather than a claimability helper.
+        # Per IRC § 221(c), no deduction "to an individual" for whom a
+        # section 151 deduction "is allowed to another taxpayer". The bar
+        # reaches that individual only: on a joint return the other spouse
+        # keeps the deduction for their own interest, although the Form 1040
+        # instructions bar the whole return. This turns on an actual claim,
+        # so it reads the claimed input rather than a claimability helper.
         claimed = person("claimed_as_dependent_on_another_return", period)
-        filer_claimed = person.tax_unit.any(head_or_spouse & claimed)
         # Per IRC § 221(e)(2), taxpayer cannot file as Married Filing Separately
         filing_status = person.tax_unit("filing_status", period)
         separate = filing_status == filing_status.possible_values.SEPARATE
-        return head_or_spouse & ~separate & ~filer_claimed
+        return head_or_spouse & ~separate & ~claimed
diff --git a/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_magi.py b/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_magi.py
index 5fa8a8768cc..e5717748c10 100644
--- a/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_magi.py
+++ b/policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_magi.py
@@ -14,13 +14,15 @@ class student_loan_interest_ald_magi(Variable):
         "222), and after application of sections 86, 135, 137, 219 and 469. "
         "Built from gross income sources rather than adjusted gross income, "
         "which includes this deduction. On a joint return each spouse "
-        "carries half of the tax unit's deductions and exclusions."
+        "carries half of the tax unit's deductions and exclusions. Joint "
+        "MAGI includes both spouses, including one claimed as a dependent "
+        "elsewhere who cannot take the deduction."
     )
     reference = (
         "https://www.law.cornell.edu/uscode/text/26/221#b_2_C",
         "https://www.irs.gov/pub/irs-prior/p970--2024.pdf#page=36",
     )
-    defined_for = "student_loan_interest_ald_eligible"
+    defined_for = "is_tax_unit_head_or_spouse"
 
     def formula(person, period, parameters):
         p_irs = parameters(period).gov.irs
diff --git a/source_conflicts/candidates.yaml b/source_conflicts/candidates.yaml
index 025bb5dd42b..3af4376ef07 100644
--- a/source_conflicts/candidates.yaml
+++ b/source_conflicts/candidates.yaml
@@ -10252,30 +10252,29 @@ candidates:
   years:
     from: 2018
     type: tax
-  question: Does claiming one spouse as a dependent bar only that spouse's education credits and student loan interest
-    deduction, or the whole joint return?
+  question: Does claiming one spouse as a dependent bar only that spouse's education credits, or the whole joint
+    return?
   sources:
   - kind: statute
-    citation: 26 U.S.C. 25A(g)(3); 26 U.S.C. 221(c)
+    citation: 26 U.S.C. 25A(g)(3)
     url: https://www.law.cornell.edu/uscode/text/26/25A#g_3
   - kind: instructions
-    citation: Form 1040 instructions (education credits and student loan interest)
+    citation: Form 1040 instructions (education credits)
     url: https://www.irs.gov/pub/irs-prior/i1040gi--2025.pdf#page=98
   readings:
-    statute: The claimed spouse loses the benefit; the other spouse keeps their own credit or deduction.
+    statute: The claimed spouse loses the credit; the other spouse keeps their own credit.
     other: The whole joint return is barred.
   pe_us:
     follows: conflicting-source
     code:
     - policyengine_us/variables/gov/irs/credits/education/is_barred_from_education_credits_by_dependency.py
-    - policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_eligible.py
     prs:
     - https://github.com/PolicyEngine/policyengine-us/pull/10087
   state: ruled
   note: 'PE-US follows the Form 1040 instructions: a claimed head or spouse bars the whole joint return from the
-    education credits and the student loan interest deduction (is_barred_from_education_credits_by_dependency.py,
-    student_loan_interest_ald_eligible.py). Ruled October 2026; the statute-first rule now requires changing the
-    whole-return bar; verify the education-credit page anchor because the supplied URL is for student loan interest.'
+    education credits (is_barred_from_education_credits_by_dependency.py). Ruled October 2026; the statute-first
+    rule now requires changing the whole-return bar; verify the education-credit page anchor because the supplied
+    URL is for student loan interest.'
 - id: us:eitc-trust-royalties-investment-income
   program: income-tax
   years:
@@ -10760,6 +10759,36 @@ candidates:
   state: unreviewed
   note: 'The open PR follows POMS rather than the broader regulatory reading; no statutory comparison or specific
     ruling is supplied. Code not yet on main: ssi_spousal_deeming_child_allocations, ssi_ineligible_child_allocation.'
+- id: us:student-loan-interest-joint-claimed-spouse
+  program: income-tax
+  years:
+    from: 2018
+    type: tax
+  question: Does claiming one spouse as a dependent bar only that spouse's student loan interest deduction, or the
+    whole joint return?
+  sources:
+  - kind: statute
+    citation: 26 U.S.C. 221(c)
+    url: https://www.law.cornell.edu/uscode/text/26/221#c
+  - kind: instructions
+    citation: 2025 Form 1040 instructions, Schedule 1 line 21 (student loan interest deduction)
+    url: https://www.irs.gov/pub/irs-prior/i1040gi--2025.pdf#page=98
+  readings:
+    statute: Section 221(c) bars only the individual whom another taxpayer claims; the other spouse keeps the deduction
+      for their own interest.
+    other: The instructions bar the return if the filer, or the spouse on a joint return, is claimed as a dependent.
+  example: On a 2025 refund-only joint return, a head with $2,000 wages and $1,000 interest, beside a spouse claimed
+    elsewhere with $700 interest, deducts $1,000 under the statute and nothing under the instructions.
+  pe_us:
+    follows: statute
+    code:
+    - policyengine_us/variables/gov/irs/income/taxable_income/adjusted_gross_income/above_the_line_deductions/student_loan_interest/student_loan_interest_ald_eligible.py
+    prs:
+    - https://github.com/PolicyEngine/policyengine-us/pull/10577
+  state: ruled
+  note: 'Ruled 2026-10-20 for the statute by the project lead. PE-US bars only the claimed head or spouse
+    (student_loan_interest_ald_eligible.py); joint MAGI for the section 221(b)(2) phase-out still counts both spouses.
+    Split from us:education-benefits-joint-claimed-spouse, which keeps the education credits.'
 - id: us:surviving-spouse-child-gross-income-test
   program: income-tax
   years: