diff --git a/l10n_us_ca_hr_payroll/data/base.xml b/l10n_us_ca_hr_payroll/data/base.xml
index b00d6277..93ac0a62 100755
--- a/l10n_us_ca_hr_payroll/data/base.xml
+++ b/l10n_us_ca_hr_payroll/data/base.xml
@@ -36,12 +36,12 @@
         <record id="contrib_register_cador_ett" model="hr.contribution.register">
             <field name="name">Employment Training Tax</field>
             <field name="note">California Department of Taxation - Employment Training Tax</field>
-            <field name="partner_id" ref="res_partner_cador_withhold"/>
+            <field name="partner_id" ref="res_partner_cador_ett"/>
         </record>
             <record id="contrib_register_cador_sdi" model="hr.contribution.register">
             <field name="name">State Disability Insurance</field>
             <field name="note">California Department of Taxation - State Disability Insurance</field>
-            <field name="partner_id" ref="res_partner_cador_withhold"/>
+            <field name="partner_id" ref="res_partner_cador_sdi"/>
         </record>
 
 
diff --git a/l10n_us_ca_hr_payroll/data/rules_2018.xml b/l10n_us_ca_hr_payroll/data/rules_2018.xml
index dd8c7d6e..e74376a1 100755
--- a/l10n_us_ca_hr_payroll/data/rules_2018.xml
+++ b/l10n_us_ca_hr_payroll/data/rules_2018.xml
@@ -87,7 +87,7 @@ result = categories.CA_ETT_WAGES
 if result_rate == 0.0:
     result = 0.0
         </field>
-        <field name="register_id" ref="contrib_register_cador_sdi"/>
+        <field name="register_id" ref="contrib_register_cador_ett"/>
         <field name="appears_on_payslip" eval="False"/>
     </record>
 
diff --git a/l10n_us_ks_hr_payroll/data/rules_2018.xml b/l10n_us_ks_hr_payroll/data/rules_2018.xml
index 29b9110c..ea88f973 100755
--- a/l10n_us_ks_hr_payroll/data/rules_2018.xml
+++ b/l10n_us_ks_hr_payroll/data/rules_2018.xml
@@ -60,11 +60,14 @@ allowances = contract.ks_k4_allowances
 additional_withholding = contract.ks_additional_withholding
 schedule_pay = contract.schedule_pay
 filing_status = contract.ks_k4_filing_status
+tax_rate_table = []
 
 # Tables are found in https://www.ksrevenue.org/pdf/kw1002017.pdf
 # First check for exemption status (Step 1)
 if filing_status == 'exempt':
     result = 0
+elif wages &lt;= 0:
+    result = 0
 
 else:
     # Calculate Withholding Allowance Amounts using table (allowance multipliers are from table).
@@ -94,7 +97,7 @@ else:
             (float('inf'), 0.057, 24.09),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (144, 0.0, 0.0),
             (721, 0.031, 0.0),
@@ -112,7 +115,7 @@ else:
             (float('inf'), 0.057, 48.17),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (288, 0.0, 0.0),
             (1442, 0.031, 0.0),
@@ -130,7 +133,7 @@ else:
             (float('inf'), 0.057, 52.19),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (313, 0.0, 0.0),
             (1563, 0.031, 0.0),
@@ -148,7 +151,7 @@ else:
             (float('inf'), 0.057, 104.38),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (625, 0.0, 0.0),
             (3125, 0.031, 0.0),
@@ -166,7 +169,7 @@ else:
             (float('inf'), 0.057, 313.13),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (1875, 0.0, 0.0),
             (9375, 0.031, 0.0),
@@ -184,7 +187,7 @@ else:
             (float('inf'), 0.057, 626.25),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (3750, 0.0, 0.0),
             (18750, 0.031, 0.0),
@@ -202,7 +205,7 @@ else:
             (float('inf'), 0.057, 1252.50),
             ]
 
-        elif filing_status == 'married':
+        elif filing_status == 'married' and wages > 0:
             tax_rate_table = [
             (7500, 0.0, 0.0),
             (37500, 0.031, 0.0),
diff --git a/l10n_us_nc_hr_payroll/data/rules_2018.xml b/l10n_us_nc_hr_payroll/data/rules_2018.xml
index 58e1f83a..d73ba291 100755
--- a/l10n_us_nc_hr_payroll/data/rules_2018.xml
+++ b/l10n_us_nc_hr_payroll/data/rules_2018.xml
@@ -95,7 +95,11 @@ else:
 if contract.nc_nc4_filing_status == 'exempt':
     result = 0
 else:
-    result = -round(((wages - (PST + (allowance_multiplier * allowances))) * 0.05599) + contract.nc_nc4_additional_wh)
+    withholding = round(((wages - (PST + (allowance_multiplier * allowances))) * 0.05599) + contract.nc_nc4_additional_wh)
+    if withholding > 0.0:
+        result = - withholding
+    else:
+        result = 0
 
         </field>
         <field name="register_id" ref="contrib_register_ncdor_withhold"/>
diff --git a/l10n_us_nc_hr_payroll/tests/test_us_nc_payslip_2018.py b/l10n_us_nc_hr_payroll/tests/test_us_nc_payslip_2018.py
index 249acc27..d7d34a0d 100755
--- a/l10n_us_nc_hr_payroll/tests/test_us_nc_payslip_2018.py
+++ b/l10n_us_nc_hr_payroll/tests/test_us_nc_payslip_2018.py
@@ -379,3 +379,40 @@ class TestUsNCPayslip(TestUsPayslip):
 
         self.assertPayrollEqual(cats['NC_UNEMP_WAGES'], remaining_nc_unemp_wages)
         self.assertPayrollEqual(cats['NC_UNEMP'], remaining_nc_unemp_wages * nc_unemp)
+
+    def test_underflow(self):
+        salary = 150.0
+        schedule_pay = 'weekly'
+        # allowance_multiplier and Portion of Standard Deduction for weekly
+        allowance_multiplier = 48.08
+        PST = 168.27
+
+        exemption = 1
+
+        #  Withholding should be 0, since pay is so low it's less than PST.
+        wh = 0.0
+
+        employee = self._createEmployee()
+        employee.company_id.nc_unemp_rate_2018 = 0.06
+
+        contract = self._createContract(employee, salary, struct_id=self.ref(
+            'l10n_us_nc_hr_payroll.hr_payroll_salary_structure_us_nc_employee'), schedule_pay=schedule_pay)
+        contract.nc_nc4_allowances = exemption
+
+        self.assertEqual(contract.schedule_pay, 'weekly')
+
+        # tax rates
+        nc_unemp = contract.nc_unemp_rate(2018) / -100.0
+
+        self._log('2018 North Carolina tax first payslip weekly:')
+        payslip = self._createPayslip(employee, '2018-01-01', '2018-01-31')
+
+        payslip.compute_sheet()
+
+        cats = self._getCategories(payslip)
+
+        self.assertPayrollEqual(cats['NC_UNEMP_WAGES'], salary)
+        self.assertPayrollEqual(cats['NC_UNEMP'], cats['NC_UNEMP_WAGES'] * nc_unemp)
+        self.assertPayrollEqual(cats['NC_INC_WITHHOLD'], wh)
+
+        process_payslip(payslip)