diff --git a/changelog_entry.yaml b/changelog_entry.yaml
index e69de29bb2d..c16f9c28de8 100644
--- a/changelog_entry.yaml
+++ b/changelog_entry.yaml
@@ -0,0 +1,4 @@
+- bump: minor
+  changes:
+    added:
+    - Second earner tax reform.
diff --git a/policyengine_us/parameters/gov/contrib/second_earner_reform/in_effect.yaml b/policyengine_us/parameters/gov/contrib/second_earner_reform/in_effect.yaml
new file mode 100644
index 00000000000..cac1ed5af90
--- /dev/null
+++ b/policyengine_us/parameters/gov/contrib/second_earner_reform/in_effect.yaml
@@ -0,0 +1,8 @@
+description: The second earner tax reform is in effect if this is true.
+metadata:
+  unit: bool
+  period: year
+  label: Second earner tax reform in effect
+
+values:
+  0000-01-01: false
diff --git a/policyengine_us/reforms/reforms.py b/policyengine_us/reforms/reforms.py
index 4101c22da74..10c69f679eb 100644
--- a/policyengine_us/reforms/reforms.py
+++ b/policyengine_us/reforms/reforms.py
@@ -62,6 +62,9 @@
 from .ctc import (
     create_ctc_older_child_supplement_reform,
 )
+from .second_earner import (
+    create_second_earner_tax_reform,
+)
 
 
 from policyengine_core.reforms import Reform
@@ -142,6 +145,9 @@ def create_structural_reforms_from_parameters(parameters, period):
     ctc_older_child_supplement = create_ctc_older_child_supplement_reform(
         parameters, period
     )
+    second_earner_tax_reform = create_second_earner_tax_reform(
+        parameters, period
+    )
 
     reforms = [
         afa_reform,
@@ -172,6 +178,7 @@ def create_structural_reforms_from_parameters(parameters, period):
         salt_phase_out,
         repeal_state_dependent_exemptions,
         ctc_older_child_supplement,
+        second_earner_tax_reform,
     ]
     reforms = tuple(filter(lambda x: x is not None, reforms))
 
diff --git a/policyengine_us/reforms/second_earner/__init__.py b/policyengine_us/reforms/second_earner/__init__.py
new file mode 100644
index 00000000000..6006de61600
--- /dev/null
+++ b/policyengine_us/reforms/second_earner/__init__.py
@@ -0,0 +1,3 @@
+from .second_earner_tax_reform import (
+    create_second_earner_tax_reform,
+)
diff --git a/policyengine_us/reforms/second_earner/second_earner_tax_reform.py b/policyengine_us/reforms/second_earner/second_earner_tax_reform.py
new file mode 100644
index 00000000000..7e8eeebd387
--- /dev/null
+++ b/policyengine_us/reforms/second_earner/second_earner_tax_reform.py
@@ -0,0 +1,820 @@
+from policyengine_us.model_api import *
+
+
+def create_second_earner_tax() -> Reform:
+
+    class is_primary_earner(Variable):
+        value_type = bool
+        entity = Person
+        label = "Whether this person is the primary earner in their tax unit"
+        definition_period = YEAR
+
+        def formula(person, period, parameters):
+            earned_income = person("earned_income", period)
+            is_tax_unit_head_or_spouse = person(
+                "is_tax_unit_head_or_spouse", period
+            )
+            is_tax_unit_head = person("is_tax_unit_head", period)
+            is_tax_unit_dependent = person("is_tax_unit_dependent", period)
+
+            # Add dependent income to head's income
+            dependent_income = (earned_income * is_tax_unit_dependent).sum()
+            earner_income = earned_income * is_tax_unit_head_or_spouse
+            earner_income = where(
+                is_tax_unit_head,
+                earner_income + dependent_income,
+                earner_income,
+            )
+
+            max_income = person.tax_unit.max(earner_income)
+            return (earner_income == max_income) & (
+                (
+                    earner_income
+                    > person.tax_unit.max(
+                        where(~is_tax_unit_head, earner_income, 0)
+                    )
+                )
+                | is_tax_unit_head
+            )
+
+    class taxable_income_person(Variable):
+        value_type = float
+        entity = Person
+        label = "IRS taxable income for each person"
+        unit = USD
+        definition_period = YEAR
+
+        def formula(person, period, parameters):
+            agi = person("adjusted_gross_income_person", period)
+            exemption_amount = person.tax_unit("exemptions", period)
+            is_joint = person.tax_unit("tax_unit_is_joint", period)
+            exemptions = where(
+                is_joint, exemption_amount / 2, exemption_amount
+            )
+            deductions = person("taxable_income_deductions_person", period)
+            return max_(0, agi - exemptions - deductions)
+
+    class income_tax_main_rates(Variable):
+        value_type = float
+        entity = TaxUnit
+        definition_period = YEAR
+        label = "Income tax main rates"
+        reference = "https://www.law.cornell.edu/uscode/text/26/1"
+        unit = USD
+
+        def formula(tax_unit, period, parameters):
+            person = tax_unit.members
+            full_taxable_income = person("taxable_income_person", period)
+            is_tax_unit_head_or_spouse = person(
+                "is_tax_unit_head_or_spouse", period
+            )
+            cg_exclusion = (
+                tax_unit("capital_gains_excluded_from_taxable_income", period)
+                / 2
+            ) * is_tax_unit_head_or_spouse
+            taxinc = max_(0, full_taxable_income - cg_exclusion)
+            p = parameters(period).gov.irs.income
+            bracket_tops = p.bracket.thresholds
+            bracket_rates = p.bracket.rates
+            filing_status = tax_unit("filing_status", period)
+
+            # Determine primary and secondary earner incomes based on income size
+            is_tax_unit_dependent = person("is_tax_unit_dependent", period)
+
+            # Add dependent income to head's income
+            dependent_income = (taxinc * is_tax_unit_dependent).sum()
+            earner_taxinc = taxinc * is_tax_unit_head_or_spouse
+
+            is_primary_earner = person("is_primary_earner", period)
+            is_secondary_earner = (
+                is_tax_unit_head_or_spouse & ~is_primary_earner
+            )
+
+            taxable_income_primary_earner = where(
+                is_primary_earner, earner_taxinc + dependent_income, 0
+            ).sum()
+            taxable_income_secondary_earner = where(
+                is_secondary_earner, earner_taxinc, 0
+            ).sum()
+
+            # Calculate primary earner tax using actual filing status
+            primary_earner_tax = 0
+            bracket_bottom = 0
+            for i in range(1, len(list(bracket_rates.__iter__())) + 1):
+                b = str(i)
+                bracket_top = bracket_tops[b][filing_status]
+                primary_earner_tax += bracket_rates[b] * amount_between(
+                    taxable_income_primary_earner, bracket_bottom, bracket_top
+                )
+                bracket_bottom = bracket_top
+
+            # Calculate secondary earner tax using single filing status
+            secondary_earner_tax = 0
+            bracket_bottom = 0
+            single_status = "SINGLE"
+            for i in range(1, len(list(bracket_rates.__iter__())) + 1):
+                b = str(i)
+                bracket_top = bracket_tops[b][single_status]
+                secondary_earner_tax += bracket_rates[b] * amount_between(
+                    taxable_income_secondary_earner,
+                    bracket_bottom,
+                    bracket_top,
+                )
+                bracket_bottom = bracket_top
+
+            return primary_earner_tax + secondary_earner_tax
+
+    class basic_standard_deduction_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Basic standard deduction"
+        definition_period = YEAR
+        unit = USD
+        reference = "https://www.law.cornell.edu/uscode/text/26/63#c_2"
+
+        def formula(person, period, parameters):
+            std = parameters(period).gov.irs.deductions.standard
+            filing_status = person.tax_unit("filing_status", period)
+            separate_filer_itemizes = person.tax_unit(
+                "separate_filer_itemizes", period
+            )
+            dependent_elsewhere = person.tax_unit(
+                "head_is_dependent_elsewhere", period
+            )
+            # Determine primary and secondary earners
+            is_tax_unit_head_or_spouse = person(
+                "is_tax_unit_head_or_spouse", period
+            )
+            is_primary_earner = person("is_primary_earner", period)
+            is_secondary_earner = (
+                is_tax_unit_head_or_spouse & ~is_primary_earner
+            )
+
+            # Calculate primary earner deduction using actual filing status
+            primary_deduction = std.amount[filing_status]
+
+            # Calculate secondary earner deduction using single filing status
+            secondary_deduction = std.amount["SINGLE"]
+            # Combine deductions based on earner status
+            standard_deduction = where(
+                is_primary_earner,
+                primary_deduction,
+                where(is_secondary_earner, secondary_deduction, 0),
+            )
+
+            standard_deduction_if_dependent = min_(
+                standard_deduction,
+                max_(
+                    std.dependent.additional_earned_income
+                    + person.tax_unit("tax_unit_earned_income", period),
+                    std.dependent.amount,
+                ),
+            )
+
+            return select(
+                [
+                    separate_filer_itemizes,
+                    dependent_elsewhere,
+                    True,
+                ],
+                [
+                    0,
+                    standard_deduction_if_dependent,
+                    standard_deduction,
+                ],
+            )
+
+    class additional_standard_deduction_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Additional standard deduction for each person"
+        unit = USD
+        definition_period = YEAR
+        reference = "https://www.law.cornell.edu/uscode/text/26/63#f"
+
+        def formula(person, period, parameters):
+            std = parameters(period).gov.irs.deductions.standard
+            filing_status = person.tax_unit("filing_status", period)
+            is_blind = person("is_blind", period).astype(int)
+            age_threshold = parameters(
+                period
+            ).gov.irs.deductions.standard.aged_or_blind.age_threshold
+            is_aged = (person("age", period) >= age_threshold).astype(int)
+            aged_blind = is_blind + is_aged
+            primary_earner = person("is_primary_earner", period)
+            amount = where(
+                primary_earner,
+                std.aged_or_blind.amount[filing_status],
+                std.aged_or_blind.amount["SINGLE"],
+            )
+            return aged_blind * amount
+
+    class bonus_guaranteed_deduction_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Bonus guaranteed deduction"
+        unit = USD
+        definition_period = YEAR
+        reference = "https://waysandmeans.house.gov/malliotakis-steel-lead-legislation-to-provide-tax-relief-to-working-families/"
+
+        def formula(person, period, parameters):
+            filing_status = person.tax_unit("filing_status", period)
+            wftca = parameters(
+                period
+            ).gov.contrib.congress.wftca.bonus_guaranteed_deduction
+            primary_earner = person("is_primary_earner", period)
+            amount = where(
+                primary_earner,
+                wftca.amount[filing_status],
+                wftca.amount["SINGLE"],
+            )
+            agi = person("adjusted_gross_income_person", period)
+            threshold = where(
+                primary_earner,
+                wftca.phase_out.threshold[filing_status],
+                wftca.phase_out.threshold["SINGLE"],
+            )
+            income_in_phase_out_region = max_(agi - threshold, 0)
+            reduction = wftca.phase_out.rate * income_in_phase_out_region
+            return max_(amount - reduction, 0)
+
+    class standard_deduction_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Standard deduction for each person"
+        unit = USD
+        definition_period = YEAR
+        reference = "https://www.law.cornell.edu/uscode/text/26/63#c"
+
+        def formula(person, period, parameters):
+            basic_deduction = person("basic_standard_deduction_person", period)
+            additional_deduction = person(
+                "additional_standard_deduction_person", period
+            )
+            bonus_deduction = person(
+                "bonus_guaranteed_deduction_person", period
+            )
+            return basic_deduction + additional_deduction + bonus_deduction
+
+    class taxable_income_deductions_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Taxable income deductions for each person"
+        unit = USD
+        definition_period = YEAR
+
+        def formula(person, period, parameters):
+            itemizes = person.tax_unit("tax_unit_itemizes", period)
+            is_joint = person.tax_unit("tax_unit_is_joint", period)
+            deductions_if_itemizing_amount = person.tax_unit(
+                "taxable_income_deductions_if_itemizing", period
+            )
+            deductions_if_itemizing = where(
+                is_joint,
+                deductions_if_itemizing_amount / 2,
+                deductions_if_itemizing_amount,
+            )
+            standard_deduction = person("standard_deduction_person", period)
+            qbid = person("qualified_business_income_deduction_person", period)
+            return where(
+                itemizes, deductions_if_itemizing, standard_deduction + qbid
+            )
+
+    class net_capital_gain_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Net capital gain"
+        unit = USD
+        documentation = (
+            "The excess of net long-term capital gain over net short-term capital"
+            'loss, plus qualified dividends (the definition of "net capital gain"'
+            "which applies to 26 U.S.C. § 1(h) from § 1(h)(11))."
+        )
+        definition_period = YEAR
+        reference = dict(
+            title="26 U.S. Code § 1222(11)",
+            href="https://www.law.cornell.edu/uscode/text/26/1222#11",
+        )
+
+        def formula(person, period, parameters):
+            lt_capital_gain = person("long_term_capital_gains", period)
+            st_capital_loss = -person("short_term_capital_gains", period)
+            net_cap_gain = max_(0, lt_capital_gain - st_capital_loss)
+            qual_div_income = person("qualified_dividend_income", period)
+            return net_cap_gain + qual_div_income
+
+    class adjusted_net_capital_gain_person(Variable):
+        value_type = float
+        entity = Person
+        label = "Adjusted net capital gain"
+        unit = USD
+        documentation = "The excess of net long-term capital gain over net short-term capital loss."
+        definition_period = YEAR
+        reference = dict(
+            title="26 U.S. Code § 1(h)(3)",
+            href="https://www.law.cornell.edu/uscode/text/26/1#h_3",
+        )
+        defined_for = "is_tax_unit_head_or_spouse"
+
+        def formula(person, period, parameters):
+            net_capital_gain = person("net_capital_gain_person", period)
+            # The law actually uses the original definition of 'net capital gain' which does not include
+            # qualified dividend income, but separately adds qualified dividends here. The definition of
+            # 'net capital gain' in the variable 'net_capital_gain' actually has some very specific exclusion
+            # criteria for particular types of dividends and companies, so it's not an *exact* fit to the
+            # definition here, but it's a good enough approximation. See 26 U.S. Code § 1(h)(11)(B) for the
+            # definition of 'net capital gain' for the above variable, and 26 U.S. Code § 1(h)(3) for the definition
+            # of adjusted net capital gain (this variable).
+            qualified_dividend_income = person(
+                "qualified_dividend_income", period
+            )
+            is_joint = person.tax_unit("tax_unit_is_joint", period)
+            divisor = where(is_joint, 2, 1)
+            unrecaptured_s_1250_gain = (
+                person.tax_unit("unrecaptured_section_1250_gain", period)
+                / divisor
+            )
+            cg_28_pct_rate_gain = (
+                person.tax_unit("capital_gains_28_percent_rate_gain", period)
+                / divisor
+            )
+            net_gains_less_dividends = max_(
+                0,
+                net_capital_gain - qualified_dividend_income,
+            )
+            reduced_capital_gains = max_(
+                net_gains_less_dividends
+                - (unrecaptured_s_1250_gain + cg_28_pct_rate_gain),
+                0,
+            )
+            return reduced_capital_gains + qualified_dividend_income
+
+    class capital_gains_tax(Variable):
+        value_type = float
+        entity = TaxUnit
+        label = "Maximum income tax after capital gains tax"
+        unit = USD
+        definition_period = YEAR
+
+        def formula(tax_unit, period, parameters):
+            person = tax_unit.members
+            net_cg = person("net_capital_gain_person", period)
+            taxable_income = person("taxable_income_person", period)
+            adjusted_net_cg = min_(
+                person("adjusted_net_capital_gain_person", period),
+                taxable_income,
+            )  # ANCG is referred to in all cases as ANCG or taxable income if less.
+
+            cg = parameters(period).gov.irs.capital_gains
+
+            excluded_cg = tax_unit(
+                "capital_gains_excluded_from_taxable_income", period
+            )
+            non_cg_taxable_income = max_(0, taxable_income - excluded_cg)
+
+            filing_status = tax_unit("filing_status", period)
+            is_tax_unit_head_or_spouse = person(
+                "is_tax_unit_head_or_spouse", period
+            )
+            is_primary_earner = person("is_primary_earner", period)
+            is_secondary_earner = (
+                is_tax_unit_head_or_spouse & ~is_primary_earner
+            )
+            is_tax_unit_dependent = person("is_tax_unit_dependent", period)
+            # Split capital gains between primary and secondary earners
+            primary_cg = where(is_primary_earner, adjusted_net_cg, 0)
+            secondary_cg = where(is_secondary_earner, adjusted_net_cg, 0)
+            dependent_cg = where(
+                is_tax_unit_dependent, adjusted_net_cg, 0
+            ).sum()
+            primary_cg += dependent_cg  # Add dependent gains to primary earner
+
+            # Calculate primary earner capital gains tax (using filing status thresholds)
+            first_threshold_primary = cg.brackets.thresholds["1"][
+                filing_status
+            ]
+            second_threshold_primary = cg.brackets.thresholds["2"][
+                filing_status
+            ]
+
+            # Calculate secondary earner capital gains tax (using single thresholds)
+            first_threshold_secondary = cg.brackets.thresholds["1"]["SINGLE"]
+            second_threshold_secondary = cg.brackets.thresholds["2"]["SINGLE"]
+
+            # Calculate brackets for primary earner
+            primary_cg_in_first = clip(primary_cg, 0, first_threshold_primary)
+            primary_cg_in_second = clip(
+                primary_cg - first_threshold_primary,
+                0,
+                second_threshold_primary - first_threshold_primary,
+            )
+            primary_cg_in_third = max_(
+                0, primary_cg - second_threshold_primary
+            )
+
+            # Calculate brackets for secondary earner
+            secondary_cg_in_first = clip(
+                secondary_cg, 0, first_threshold_secondary
+            )
+            secondary_cg_in_second = clip(
+                secondary_cg - first_threshold_secondary,
+                0,
+                second_threshold_secondary - first_threshold_secondary,
+            )
+            secondary_cg_in_third = max_(
+                0, secondary_cg - second_threshold_secondary
+            )
+
+            # Calculate total capital gains tax
+            main_cg_tax = (
+                (primary_cg_in_first + secondary_cg_in_first)
+                * cg.brackets.rates["1"]
+                + (primary_cg_in_second + secondary_cg_in_second)
+                * cg.brackets.rates["2"]
+                + (primary_cg_in_third + secondary_cg_in_third)
+                * cg.brackets.rates["3"]
+            )
+            is_joint = tax_unit("tax_unit_is_joint", period)
+            divisor = where(is_joint, 2, 1)
+            unrecaptured_s_1250_gain = (
+                tax_unit("unrecaptured_section_1250_gain", period) / divisor
+            )
+            qualified_dividends = (
+                add(tax_unit, period, ["qualified_dividend_income"]) / divisor
+            )
+            max_taxable_unrecaptured_gain = min_(
+                unrecaptured_s_1250_gain,
+                max_(0, net_cg - qualified_dividends),
+            )
+            unrecaptured_gain_deduction = max_(
+                non_cg_taxable_income + net_cg - taxable_income,
+                0,
+            )
+            taxable_unrecaptured_gain = max_(
+                max_taxable_unrecaptured_gain - unrecaptured_gain_deduction,
+                0,
+            )
+
+            unrecaptured_gain_tax = (
+                cg.unrecaptured_s_1250_rate * taxable_unrecaptured_gain
+            )
+
+            remaining_cg_tax = (
+                tax_unit("capital_gains_28_percent_rate_gain", period)
+                * cg.other_cg_rate
+            ) / divisor
+            return tax_unit.sum(
+                main_cg_tax + unrecaptured_gain_tax + remaining_cg_tax
+            )
+
+    class amt_excluded_deductions_person(Variable):
+        value_type = float
+        entity = Person
+        definition_period = YEAR
+        label = "AMT taxable income excluded deductions"
+        unit = USD
+        reference = "https://www.law.cornell.edu/uscode/text/26/55#b_2"
+
+        def formula(person, period, parameters):
+            itemizing = person.tax_unit("tax_unit_itemizes", period)
+            standard_deduction = person("standard_deduction_person", period)
+            is_joint = person.tax_unit("tax_unit_is_joint", period)
+            divisor = where(is_joint, 2, 1)
+            salt_deduction = (
+                person.tax_unit("salt_deduction", period) / divisor
+            )
+            return where(itemizing, salt_deduction, standard_deduction)
+
+    class amt_income_person(Variable):
+        value_type = float
+        entity = Person
+        definition_period = YEAR
+        label = "AMT taxable income"
+        unit = USD
+        reference = "https://www.law.cornell.edu/uscode/text/26/55#b_2"
+        defined_for = "is_tax_unit_head_or_spouse"
+
+        def formula(person, period, parameters):
+            taxable_income = person("taxable_income_person", period)
+            deductions = person("amt_excluded_deductions_person", period)
+            is_joint = person.tax_unit("tax_unit_is_joint", period)
+            divisor = where(is_joint, 2, 1)
+            separate_addition = (
+                person.tax_unit("amt_separate_addition", period) / divisor
+            )
+            return taxable_income + deductions + separate_addition
+
+    class alternative_minimum_tax(Variable):
+        value_type = float
+        entity = TaxUnit
+        definition_period = YEAR
+        label = "Alternative Minimum Tax"
+        unit = USD
+        documentation = "Alternative Minimum Tax (AMT) liability"
+
+        def formula(tax_unit, period, parameters):
+            person = tax_unit.members
+            amt_income = person("amt_income_person", period)
+            # Form 6251, Part II top
+            p = parameters(period).gov.irs.income.amt
+            phase_out = p.exemption.phase_out
+            filing_status = tax_unit("filing_status", period)
+
+            # Split calculations for primary and secondary earners
+            is_primary_earner = person("is_primary_earner", period)
+            is_secondary_earner = (
+                person("is_tax_unit_head_or_spouse", period)
+                & ~is_primary_earner
+            )
+            is_tax_unit_dependent = person("is_tax_unit_dependent", period)
+
+            # Primary earner uses filing status thresholds
+            primary_base_exemption = p.exemption.amount[filing_status]
+            primary_phase_out_start = phase_out.start[filing_status]
+
+            # Secondary earner uses single thresholds
+            secondary_base_exemption = p.exemption.amount["SINGLE"]
+            secondary_phase_out_start = phase_out.start["SINGLE"]
+
+            # Calculate income for each earner
+            primary_income = where(is_primary_earner, amt_income, 0)
+            secondary_income = where(is_secondary_earner, amt_income, 0)
+            dependent_income = where(
+                is_tax_unit_dependent, amt_income, 0
+            ).sum()
+            primary_income += (
+                dependent_income  # Add dependent income to primary
+            )
+
+            # Calculate exemption amounts
+            primary_excess = max_(0, primary_income - primary_phase_out_start)
+            secondary_excess = max_(
+                0, secondary_income - secondary_phase_out_start
+            )
+
+            primary_exemption = max_(
+                0, primary_base_exemption - phase_out.rate * primary_excess
+            )
+            secondary_exemption = max_(
+                0, secondary_base_exemption - phase_out.rate * secondary_excess
+            )
+
+            age_head = tax_unit("age_head", period)
+            child = parameters(period).gov.irs.dependent.ineligible_age
+            young_head = (age_head != 0) & (age_head < child.non_student)
+            no_or_young_spouse = (
+                tax_unit("age_spouse", period) < child.non_student
+            )
+            adj_earnings = person("adjusted_earnings", period)
+            child_amount = p.exemption.child.amount
+
+            kiddie_tax_exemption_cap_applies = young_head & no_or_young_spouse
+            exemption_cap = where(
+                kiddie_tax_exemption_cap_applies,
+                adj_earnings + child_amount,
+                np.inf,
+            )
+            primary_exemption = min_(primary_exemption, exemption_cap)
+            secondary_exemption = min_(secondary_exemption, exemption_cap)
+
+            # Calculate taxable income
+            taxable_income = person("taxable_income_person", period)
+            # Do not add back deduction for filers subject to the kiddie tax
+            primary_applied_income = where(
+                kiddie_tax_exemption_cap_applies,
+                where(is_primary_earner, taxable_income, 0),
+                primary_income,
+            )
+            secondary_applied_income = where(
+                kiddie_tax_exemption_cap_applies,
+                where(is_secondary_earner, taxable_income, 0),
+                secondary_income,
+            )
+
+            primary_reduced_income = max_(
+                0, primary_applied_income - primary_exemption
+            )
+            secondary_reduced_income = max_(
+                0, secondary_applied_income - secondary_exemption
+            )
+
+            # Calculate bracket fractions
+            primary_bracket_fraction = where(
+                filing_status == filing_status.possible_values.SEPARATE,
+                0.5,
+                1.0,
+            )
+            secondary_bracket_fraction = (
+                1.0  # Single always uses full brackets
+            )
+
+            # Calculate tax thresholds
+            primary_tax_threshold = (
+                p.brackets.thresholds[-1] * primary_bracket_fraction
+            )
+            secondary_tax_threshold = (
+                p.brackets.thresholds[-1] * secondary_bracket_fraction
+            )
+
+            lower_rate = p.brackets.rates[0]
+            higher_rate = p.brackets.rates[1]
+
+            # Calculate tax for primary earner
+            primary_lower_tax = (
+                min_(primary_reduced_income, primary_tax_threshold)
+                * lower_rate
+            )
+            primary_higher_tax = (
+                max_(0, primary_reduced_income - primary_tax_threshold)
+                * higher_rate
+            )
+
+            # Calculate tax for secondary earner
+            secondary_lower_tax = (
+                min_(secondary_reduced_income, secondary_tax_threshold)
+                * lower_rate
+            )
+            secondary_higher_tax = (
+                max_(0, secondary_reduced_income - secondary_tax_threshold)
+                * higher_rate
+            )
+
+            # Combine taxes
+            reduced_income_tax = (
+                primary_lower_tax
+                + primary_higher_tax
+                + secondary_lower_tax
+                + secondary_higher_tax
+            )
+
+            dwks10, dwks13, dwks14, dwks19, e24515 = [
+                add(tax_unit, period, [variable])
+                for variable in [
+                    "dwks10",
+                    "dwks13",
+                    "dwks14",
+                    "dwks19",
+                    "unrecaptured_section_1250_gain",
+                ]
+            ]
+            form_6251_part_iii_required = np.any(
+                [
+                    variable > 0
+                    for variable in [
+                        dwks10,
+                        dwks13,
+                        dwks14,
+                        dwks19,
+                        e24515,
+                    ]
+                ]
+            )
+
+            # Complete Form 6251, Part III
+            line37 = dwks13
+            line38 = e24515
+            line39 = min_(line37 + line38, dwks10)
+            line40 = min_(
+                primary_reduced_income + secondary_reduced_income, line39
+            )
+            line41 = max_(
+                0, primary_reduced_income + secondary_reduced_income - line40
+            )
+            line42 = p.brackets.calc(line41)
+            line44 = dwks14
+
+            # Apply different thresholds for primary/secondary for capital gains
+            cg = p.capital_gains.brackets
+            primary_line45 = max_(
+                0, cg.thresholds["1"][filing_status] - line44
+            )
+            secondary_line45 = max_(0, cg.thresholds["1"]["SINGLE"] - line44)
+
+            line46 = min_(
+                primary_reduced_income + secondary_reduced_income, line37
+            )
+            primary_line47 = min_(primary_line45, line46)
+            secondary_line47 = min_(secondary_line45, line46)
+
+            cgtax1 = (
+                primary_line47 * cg.rates["1"]
+                + secondary_line47 * cg.rates["1"]
+            )
+
+            line48 = line46 - (primary_line47 + secondary_line47)
+            line51 = dwks19
+
+            primary_line52 = primary_line45 + line51
+            secondary_line52 = secondary_line45 + line51
+
+            primary_line53 = max_(
+                0, cg.thresholds["2"][filing_status] - primary_line52
+            )
+            secondary_line53 = max_(
+                0, cg.thresholds["2"]["SINGLE"] - secondary_line52
+            )
+
+            primary_line54 = min_(line48, primary_line53)
+            secondary_line54 = min_(line48, secondary_line53)
+
+            cgtax2 = (
+                primary_line54 * cg.rates["2"]
+                + secondary_line54 * cg.rates["2"]
+            )
+
+            line56 = (
+                primary_line47
+                + secondary_line47
+                + primary_line54
+                + secondary_line54
+            )
+            line57 = where(line41 == line56, 0, line46 - line56)
+            linex2 = where(
+                line41 == line56,
+                0,
+                max_(0, primary_line54 + secondary_line54 - line48),
+            )
+            cgtax3 = line57 * cg.rates["3"]
+
+            line61 = where(
+                line38 == 0,
+                0,
+                p.capital_gains.capital_gain_excess_tax_rate
+                * max_(
+                    0,
+                    (
+                        primary_reduced_income
+                        + secondary_reduced_income
+                        - line41
+                        - line56
+                        - line57
+                        - linex2
+                    ),
+                ),
+            )
+            line62 = line42 + cgtax1 + cgtax2 + cgtax3 + line61
+            line64 = min_(reduced_income_tax, line62)
+            line31 = where(
+                form_6251_part_iii_required, line64, reduced_income_tax
+            )
+
+            # Form 6251, Part II bottom
+            is_joint = tax_unit("tax_unit_is_joint", period)
+            divisor = where(is_joint, 2, 1)
+            line32 = tax_unit("foreign_tax_credit", period) / divisor
+            line33 = line31 - line32
+            regular_tax_before_credits = (
+                tax_unit("regular_tax_before_credits", period) / divisor
+            )
+            lump_sum_distributions = (
+                tax_unit("form_4972_lumpsum_distributions", period) / divisor
+            )
+            capital_gains = tax_unit("capital_gains_tax", period)
+            tax_before_credits = regular_tax_before_credits + capital_gains
+
+            return tax_unit.sum(
+                max_(
+                    0,
+                    line33
+                    - max_(
+                        0,
+                        (tax_before_credits - line32 - lump_sum_distributions),
+                    ),
+                )
+            )
+
+    class reform(Reform):
+        def apply(self):
+            self.update_variable(taxable_income_person)
+            self.update_variable(income_tax_main_rates)
+            self.update_variable(basic_standard_deduction_person)
+            self.update_variable(standard_deduction_person)
+            self.update_variable(taxable_income_deductions_person)
+            self.update_variable(is_primary_earner)
+            self.update_variable(capital_gains_tax)
+            self.update_variable(net_capital_gain_person)
+            self.update_variable(adjusted_net_capital_gain_person)
+            self.update_variable(alternative_minimum_tax)
+            self.update_variable(amt_income_person)
+            self.update_variable(amt_excluded_deductions_person)
+            self.update_variable(bonus_guaranteed_deduction_person)
+            self.update_variable(additional_standard_deduction_person)
+
+    return reform
+
+
+def create_second_earner_tax_reform(parameters, period, bypass: bool = False):
+    if bypass:
+        return create_second_earner_tax()
+
+    p = parameters(period).gov.contrib.second_earner_reform
+
+    if p.in_effect:
+        return create_second_earner_tax()
+    else:
+        return None
+
+
+second_earner_tax_reform = create_second_earner_tax_reform(
+    None, None, bypass=True
+)
diff --git a/policyengine_us/tests/policy/contrib/second_earner/second_earner_tax_reform.yaml b/policyengine_us/tests/policy/contrib/second_earner/second_earner_tax_reform.yaml
new file mode 100644
index 00000000000..02025cc3dba
--- /dev/null
+++ b/policyengine_us/tests/policy/contrib/second_earner/second_earner_tax_reform.yaml
@@ -0,0 +1,371 @@
+- name: Two people, both with income in the first bracket
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        is_tax_unit_head_or_spouse: true
+        taxable_income_person: 20_000
+      person2:
+        is_tax_unit_head_or_spouse: true
+        taxable_income_person: 1_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        capital_gains_excluded_from_taxable_income: 0
+        filing_status: JOINT
+  output:
+    income_tax_main_rates: 2_100
+
+- name: Two people, spouse in second single bracket
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        is_tax_unit_head_or_spouse: true
+        taxable_income_person: 20_000
+      person2:
+        is_tax_unit_head_or_spouse: true
+        taxable_income_person: 15_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        capital_gains_excluded_from_taxable_income: 0
+        filing_status: JOINT
+  output:
+    income_tax_main_rates: 3_580
+
+- name: Two people, spouse in second single bracket - reform not applied
+  period: 2023
+  input:
+    gov.contrib.second_earner_reform.in_effect: false
+    people: 
+      person1:
+        is_tax_unit_head_or_spouse: true
+      person2:
+        is_tax_unit_head_or_spouse: true
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        capital_gains_excluded_from_taxable_income: 0
+        filing_status: JOINT
+        taxable_income: 45_000
+  output:
+    income_tax_main_rates: 4_960
+
+
+- name: Spouse with higher income becomes primary earner
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        is_tax_unit_head_or_spouse: true
+        taxable_income_person: 20_000
+      person2:
+        is_tax_unit_head_or_spouse: true
+        taxable_income_person: 40_000
+        is_primary_earner: true
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        capital_gains_excluded_from_taxable_income: 0
+        filing_status: JOINT
+  output:
+    income_tax_main_rates: 6_540
+
+- name: One person with one dependent taxes as head of household
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        taxable_income_person: 40_000
+      person2:
+        age: 10
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        capital_gains_excluded_from_taxable_income: 0
+  output:
+    income_tax_main_rates: 4_486
+
+- name: One person alone is taxed as single
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        taxable_income_person: 15_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+        capital_gains_excluded_from_taxable_income: 0
+  output:
+    income_tax_main_rates: 1_580
+
+- name: Joint couple with one dependent, cg exclusion included
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        taxable_income_person: 30_000
+      person2:
+        age: 40
+        taxable_income_person: 15_000
+      person3:
+        age: 16
+        taxable_income_person: 1_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2, person3]
+        capital_gains_excluded_from_taxable_income: 2_000
+  output:
+    income_tax_main_rates: 4_620
+
+- name: Integration, joint household with one depedent, reform not applied
+  period: 2023
+  input:
+    gov.contrib.second_earner_reform.in_effect: false
+    people: 
+      person1:
+        age: 40
+        employment_income: 50_000
+      person2:
+        age: 40
+        employment_income: 40_000
+      person3:
+        age: 16
+        employment_income: 1_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2, person3]
+  output:
+    adjusted_gross_income: 90_000
+    adjusted_gross_income_person: [50_000, 40_000, 0]
+    exemptions: 0
+    taxable_income_deductions: 27_700
+    taxable_income: 62_300
+    income_tax_main_rates: 7_036
+
+- name: Integration, joint household with one depedent, reform applied
+  period: 2023
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        employment_income: 50_000
+      person2:
+        age: 40
+        employment_income: 40_000
+      person3:
+        age: 16
+        employment_income: 1_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2, person3]
+  output:
+    adjusted_gross_income: 90_000
+    adjusted_gross_income_person: [50_000, 40_000, 0]
+    taxable_income: 62_300
+    exemptions: 0
+    taxable_income_deductions: 27_700
+    taxable_income_deductions_person: [27_700, 13_850, 0]
+    taxable_income_person: [22_300, 26_150, 0]
+    income_tax_main_rates: 5_154
+
+
+- name: Two people both without income
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+      person2:
+        age: 40
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        filing_status: JOINT
+  output:
+    basic_standard_deduction_person: [29_200, 14_600]
+
+- name: Taxable income deductions - standard deduction case
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        earned_income: 50_000
+      person2:
+        age: 40
+        earned_income: 30_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        filing_status: JOINT
+        tax_unit_itemizes: false
+  output:
+    taxable_income_deductions_person: [29_200, 14_600]
+
+- name: Taxable income deductions - itemizing case
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        earned_income: 50_000
+      person2:
+        age: 40
+        earned_income: 30_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        filing_status: JOINT
+        tax_unit_itemizes: true
+        taxable_income_deductions_if_itemizing: 40_000
+  output:
+    taxable_income_deductions_person: [20_000, 20_000]
+
+- name: Integration test - joint household with one dependent
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:  # Head
+        age: 40
+        employment_income: 50_000
+      person2:  # Spouse
+        age: 40
+        employment_income: 30_000
+      person3:  # Dependent
+        age: 16
+        employment_income: 1_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2, person3]
+        filing_status: JOINT
+  output:
+    # Income variables
+    adjusted_gross_income: 80_000
+    adjusted_gross_income_person: [50_000, 30_000, 0]
+    taxable_income: 50_800  # AGI minus standard deduction
+    taxable_income_person: [20_800, 15_400, 0]  # Individual taxable incomes
+    # Deduction variables
+    basic_standard_deduction: 29_200
+    basic_standard_deduction_person: [29_200, 14_600, 0]  # Head gets joint, spouse gets single
+    taxable_income_deductions: 29_200
+    taxable_income_deductions_person: [29_200, 14_600, 0]
+    # Tax variables
+    income_tax_main_rates: 3_696
+
+- name: Capital gains tax test, two people with CG taxes
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        adjusted_net_capital_gain_person: 150_000
+        taxable_income_person: 150_000
+        is_tax_unit_head_or_spouse: true
+        qualified_dividend_income: 11_000
+      person2:
+        age: 40
+        is_tax_unit_head_or_spouse: true
+        adjusted_net_capital_gain_person: 100_000
+        taxable_income_person: 100_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        filing_status: JOINT
+  output:
+    capital_gains_tax: 16_338.75
+
+- name: AMT test
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        amt_income_person: 150_000
+        is_primary_earner: true
+      person2:
+        age: 40
+        amt_income_person: 100_000
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+        filing_status: JOINT
+  output:
+    alternative_minimum_tax: 8_060
+
+
+- name: Counterfactual integration test - single household with one dependent - reform not applied
+  period: 2024
+  input:
+    gov.contrib.second_earner_reform.in_effect: false
+    people: 
+      person1:
+        age: 40
+        employment_income: 150_000
+      person2:
+        age: 10
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+  output:
+    # Income variables
+    adjusted_gross_income: 150_000
+    taxable_income: 128_100  
+    # Deduction variables
+    basic_standard_deduction: 21_900
+    taxable_income_deductions: 21_900
+    # Tax variables
+    income_tax_main_rates: 22_093
+
+
+- name: Integration test - single household with one dependent - nothing should change
+  period: 2024
+  reforms: policyengine_us.reforms.second_earner.second_earner_tax_reform.second_earner_tax_reform
+  input:
+    gov.contrib.second_earner_reform.in_effect: true
+    people: 
+      person1:
+        age: 40
+        employment_income: 150_000
+      person2:
+        age: 10
+    tax_units:
+      tax_unit:
+        members: [person1, person2]
+  output:
+    # Income variables
+    adjusted_gross_income: 150_000
+    taxable_income: 128_100  
+    # Deduction variables
+    basic_standard_deduction: 21_900
+    taxable_income_deductions: 21_900
+    # Tax variables
+    income_tax_main_rates: 22_093