diff --git a/l10n_us_hr_payroll/data/state/mi_michigan.xml b/l10n_us_hr_payroll/data/state/mi_michigan.xml
index 1ce32483..df67c982 100644
--- a/l10n_us_hr_payroll/data/state/mi_michigan.xml
+++ b/l10n_us_hr_payroll/data/state/mi_michigan.xml
@@ -7,16 +7,17 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
-        <record id="rule_parameter_us_mi_suta_wage_base_2019" model="hr.rule.parameter.value">
-            <field name="parameter_value">9500.0</field>
-            <field name="rule_parameter_id" ref="rule_parameter_us_mi_suta_wage_base"/>
-            <field name="date_from" eval="datetime(2019, 1, 1).date()"/>
-        </record>
         <record id="rule_parameter_us_mi_suta_wage_base_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">9000.0</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_mi_suta_wage_base"/>
             <field name="date_from" eval="datetime(2020, 1, 1).date()"/>
         </record>
+        <!-- https://taxnews.ey.com/news/2020-2141-michigan-sui-taxable-wage-base-expected-to-increase-for-2021-due-to-covid-19s-depletion-of-ui-trust-fund#:~:text=Michigan%20employers%20should%20expect%20to,be%20used%20by%20delinquent%20employers. -->
+        <record id="rule_parameter_us_mi_suta_wage_base_2021" model="hr.rule.parameter.value">
+            <field name="parameter_value">9500.0</field>
+            <field name="rule_parameter_id" ref="rule_parameter_us_mi_suta_wage_base"/>
+            <field name="date_from" eval="datetime(2021, 1, 1).date()"/>
+        </record>
     </data>
 
     <!-- Rate -->
@@ -26,11 +27,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
-        <record id="rule_parameter_us_mi_suta_rate_2019" model="hr.rule.parameter.value">
-            <field name="parameter_value">2.7</field>
-            <field name="rule_parameter_id" ref="rule_parameter_us_mi_suta_rate"/>
-            <field name="date_from" eval="datetime(2019, 1, 1).date()"/>
-        </record>
+        <!-- same for 2021 https://www.michigan.gov/leo/0,5863,7-336-94422_97241_89981_90255-502287-  -,00.html -->
         <record id="rule_parameter_us_mi_suta_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">2.7</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_mi_suta_rate"/>
@@ -44,18 +41,21 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
-        <record id="rule_parameter_us_mi_sit_exemption_rate_2019" model="hr.rule.parameter.value">
-            <field name="parameter_value">4400.0</field>
-            <field name="rule_parameter_id" ref="rule_parameter_us_mi_sit_exemption_rate"/>
-            <field name="date_from" eval="datetime(2019, 1, 1).date()"/>
-        </record>
         <record id="rule_parameter_us_mi_sit_exemption_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">4750.0</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_mi_sit_exemption_rate"/>
             <field name="date_from" eval="datetime(2020, 1, 1).date()"/>
         </record>
+        <!-- https://www.michigan.gov/documents/taxes/446_711611_7.pdf -->
+        <record id="rule_parameter_us_mi_sit_exemption_rate_2021" model="hr.rule.parameter.value">
+            <field name="parameter_value">4900.0</field>
+            <field name="rule_parameter_id" ref="rule_parameter_us_mi_sit_exemption_rate"/>
+            <field name="date_from" eval="datetime(2021, 1, 1).date()"/>
+        </record>
     </data>
 
+    <!-- todo: income tax rate https://www.michigan.gov/taxes/0,4676,7-238-43519_43531-  -  -,00.html -->
+
     <!-- Partners and Contribution Registers -->
     <record id="res_partner_us_mi_dor" model="res.partner">
         <field name="name">US Michigan - Unemployment Insurance Agency - Unemployment Tax</field>
diff --git a/l10n_us_hr_payroll/tests/test_us_mi_michigan_payslip_2019.py b/l10n_us_hr_payroll/tests/test_us_mi_michigan_payslip_2019.py
deleted file mode 100755
index b12baed2..00000000
--- a/l10n_us_hr_payroll/tests/test_us_mi_michigan_payslip_2019.py
+++ /dev/null
@@ -1,194 +0,0 @@
-# Part of Hibou Suite Professional. See LICENSE_PROFESSIONAL file for full copyright and licensing details.
-
-from .common import TestUsPayslip, process_payslip
-
-
-class TestUsMIPayslip(TestUsPayslip):
-    # Taxes and Rates
-    MI_UNEMP_MAX_WAGE = 9500.0
-    MI_UNEMP = - 2.7 / 100.0
-    MI_INC_TAX = - 4.25 / 100.0
-    ANNUAL_EXEMPTION_AMOUNT = 4400.00
-    PAY_PERIOD_DIVISOR = {
-        'weekly': 52.0,
-        'bi-weekly': 26.0,
-        'semi-monthly': 24.0,
-        'monthly': 12.0
-    }
-
-    def test_2019_taxes_weekly(self):
-        salary = 5000.0
-        schedule_pay = 'weekly'
-        exemptions = 1
-
-        employee = self._createEmployee()
-        contract = self._createContract(employee,
-                                        wage=salary,
-                                        state_id=self.get_us_state('MI'),
-                                        state_income_tax_additional_withholding=0.0,
-                                        mi_w4_sit_exemptions=1.0,
-                                        schedule_pay='weekly')
-
-        allowance_amount = self.ANNUAL_EXEMPTION_AMOUNT / self.PAY_PERIOD_DIVISOR[schedule_pay]
-        wh = -((salary - (allowance_amount * exemptions)) * -self.MI_INC_TAX)
-
-        self._log('2019 Michigan tax first payslip weekly:')
-        payslip = self._createPayslip(employee, '2019-01-01', '2019-01-31')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], salary * self.MI_UNEMP)
-        self.assertPayrollAlmostEqual(cats['EE_US_SIT'], wh)
-    #
-        process_payslip(payslip)
-
-        # Make a new payslip, this one will have maximums
-        remaining_MI_UNEMP_wages = self.MI_UNEMP_MAX_WAGE - salary if (self.MI_UNEMP_MAX_WAGE - 2*salary < salary) \
-            else salary
-
-        self._log('2019 Michigan tax second payslip weekly:')
-        payslip = self._createPayslip(employee, '2019-02-01', '2019-02-28')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], remaining_MI_UNEMP_wages * self.MI_UNEMP)
-
-    def test_2019_taxes_biweekly(self):
-        salary = 5000.0
-        schedule_pay = 'bi-weekly'
-        allowance_amount = self.ANNUAL_EXEMPTION_AMOUNT / self.PAY_PERIOD_DIVISOR[schedule_pay]
-        exemption = 2
-
-        wh = -((salary - (allowance_amount * exemption)) * -self.MI_INC_TAX)
-
-        employee = self._createEmployee()
-        contract = self._createContract(employee,
-                                        wage=salary,
-                                        state_id=self.get_us_state('MI'),
-                                        state_income_tax_additional_withholding=0.0,
-                                        mi_w4_sit_exemptions=2.0,
-                                        schedule_pay='bi-weekly')
-
-        self._log('2019 Michigan tax first payslip bi-weekly:')
-        payslip = self._createPayslip(employee, '2019-01-01', '2019-01-31')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], salary * self.MI_UNEMP)
-        self.assertPayrollEqual(cats['EE_US_SIT'], wh)
-
-        process_payslip(payslip)
-
-        # Make a new payslip, this one will have maximums
-        remaining_MI_UNEMP_wages = self.MI_UNEMP_MAX_WAGE - salary if (self.MI_UNEMP_MAX_WAGE - 2*salary < salary) \
-            else salary
-
-        self._log('2019 Michigan tax second payslip bi-weekly:')
-        payslip = self._createPayslip(employee, '2019-02-01', '2019-02-28')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], remaining_MI_UNEMP_wages * self.MI_UNEMP)
-
-    def test_2019_taxes_semimonthly(self):
-        salary = 5000.0
-        schedule_pay = 'semi-monthly'
-        allowance_amount = self.ANNUAL_EXEMPTION_AMOUNT / self.PAY_PERIOD_DIVISOR[schedule_pay]
-        exemption = 1
-
-        wh = -((salary - (allowance_amount * exemption)) * -self.MI_INC_TAX)
-
-        employee = self._createEmployee()
-        contract = self._createContract(employee,
-                                        wage=salary,
-                                        state_id=self.get_us_state('MI'),
-                                        state_income_tax_additional_withholding=0.0,
-                                        mi_w4_sit_exemptions=1.0,
-                                        schedule_pay='semi-monthly')
-
-        self._log('2019 Michigan tax first payslip semi-monthly:')
-        payslip = self._createPayslip(employee, '2019-01-01', '2019-01-31')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], salary * self.MI_UNEMP)
-        self.assertPayrollEqual(cats['EE_US_SIT'], wh)
-
-        process_payslip(payslip)
-
-        # Make a new payslip, this one will have maximums
-        remaining_MI_UNEMP_wages = self.MI_UNEMP_MAX_WAGE - salary if (self.MI_UNEMP_MAX_WAGE - 2 * salary < salary) \
-            else salary
-
-        self._log('2019 Michigan tax second payslip semi-monthly:')
-        payslip = self._createPayslip(employee, '2019-02-01', '2019-02-28')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], remaining_MI_UNEMP_wages * self.MI_UNEMP)
-
-    def test_2019_taxes_monthly(self):
-        salary = 5000.0
-        schedule_pay = 'monthly'
-        allowance_amount = self.ANNUAL_EXEMPTION_AMOUNT / self.PAY_PERIOD_DIVISOR[schedule_pay]
-        exemption = 1
-
-        wh = -((salary - (allowance_amount * exemption)) * -self.MI_INC_TAX)
-
-        employee = self._createEmployee()
-        contract = self._createContract(employee,
-                                        wage=salary,
-                                        state_id=self.get_us_state('MI'),
-                                        state_income_tax_additional_withholding=0.0,
-                                        mi_w4_sit_exemptions=1.0,
-                                        schedule_pay='monthly')
-
-        self._log('2019 Michigan tax first payslip monthly:')
-        payslip = self._createPayslip(employee, '2019-01-01', '2019-01-31')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], salary * self.MI_UNEMP)
-        self.assertPayrollEqual(cats['EE_US_SIT'], wh)
-
-        process_payslip(payslip)
-
-        # Make a new payslip, this one will have maximums
-        remaining_MI_UNEMP_wages = self.MI_UNEMP_MAX_WAGE - salary if (
-                    self.MI_UNEMP_MAX_WAGE - (2 * salary) < salary) \
-            else salary
-
-        self._log('2019 Michigan tax second payslip monthly:')
-        payslip = self._createPayslip(employee, '2019-02-01', '2019-02-28')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], remaining_MI_UNEMP_wages * self.MI_UNEMP)
-
-    def test_additional_withholding(self):
-        salary = 5000.0
-        schedule_pay = 'weekly'
-        allowance_amount = 0.0
-        allowance_amount = self.ANNUAL_EXEMPTION_AMOUNT / self.PAY_PERIOD_DIVISOR[schedule_pay]
-        additional_wh = 40.0
-        exemption = 1
-
-        wh = -(((salary - (allowance_amount * exemption)) * -self.MI_INC_TAX) + additional_wh)
-
-        employee = self._createEmployee()
-        contract = self._createContract(employee,
-                                        wage=salary,
-                                        state_id=self.get_us_state('MI'),
-                                        state_income_tax_additional_withholding=40.0,
-                                        mi_w4_sit_exemptions=1.0,
-                                        schedule_pay='weekly')
-
-        self._log('2019 Michigan tax first payslip with additional withholding:')
-        payslip = self._createPayslip(employee, '2019-01-01', '2019-01-31')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['ER_US_SUTA'], salary * self.MI_UNEMP)
-        self.assertPayrollAlmostEqual(cats['EE_US_SIT'], wh)
-
-        process_payslip(payslip)
diff --git a/l10n_us_hr_payroll/tests/test_us_mi_michigan_payslip_2021.py b/l10n_us_hr_payroll/tests/test_us_mi_michigan_payslip_2021.py
new file mode 100755
index 00000000..690749f8
--- /dev/null
+++ b/l10n_us_hr_payroll/tests/test_us_mi_michigan_payslip_2021.py
@@ -0,0 +1,35 @@
+# Part of Hibou Suite Professional. See LICENSE_PROFESSIONAL file for full copyright and licensing details.
+
+from datetime import date, timedelta
+from .common import TestUsPayslip
+
+
+class TestUsMIPayslip(TestUsPayslip):
+    # Taxes and Rates
+    MI_UNEMP_MAX_WAGE = 9500.0
+    MI_UNEMP = 2.7
+
+    def _test_sit(self, wage, exemptions, additional_withholding, schedule_pay, date_start, expected_withholding):
+
+        employee = self._createEmployee()
+        contract = self._createContract(employee,
+                                        wage=wage,
+                                        state_id=self.get_us_state('MI'),
+                                        mi_w4_sit_exemptions=exemptions,
+                                        state_income_tax_additional_withholding=additional_withholding,
+                                        schedule_pay=schedule_pay)
+        payslip = self._createPayslip(employee, date_start, date_start + timedelta(days=7))
+        payslip.compute_sheet()
+        cats = self._getCategories(payslip)
+
+        self._log('Computed period tax: ' + str(expected_withholding))
+        self.assertPayrollEqual(cats.get('EE_US_SIT', 0.0), -expected_withholding)
+
+    def test_2021_taxes_example(self):
+        self._test_er_suta('MI', self.MI_UNEMP, date(2021, 1, 1), wage_base=self.MI_UNEMP_MAX_WAGE)
+        self._test_sit(750.0, 1, 100.0, 'weekly', date(2021, 1, 1), 127.87)
+        self._test_sit(1750.0, 1, 0.0, 'bi-weekly', date(2021, 1, 1), 66.37)
+        self._test_sit(5000.0, 1, 5.0, 'semi-monthly', date(2021, 1, 1), 208.83)
+        self._test_sit(8000.0, 1, 5.0, 'monthly', date(2021, 1, 1), 327.65)
+        self._test_sit(5000.0, 2, 0.0, 'monthly', date(2021, 1, 1), 177.79)
+