diff --git a/pytest.ini b/pytest.ini
index e31fa6c8..0b46accd 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -6,3 +6,4 @@ markers =
     taxexp
     qbid
     taxexpdiffs
+    itax
diff --git a/tests/test_misc.py b/tests/test_misc.py
index 7e1bda11..9baddf9f 100644
--- a/tests/test_misc.py
+++ b/tests/test_misc.py
@@ -2,6 +2,10 @@
 Miscellaneous tests of tmd.csv variable weighted totals.
 """
 
+import pytest
+import taxcalc as tc
+from tmd.storage import STORAGE_FOLDER
+
 
 def test_no_negative_weights(tmd_variables):
     assert tmd_variables.s006.min() >= 0, "Negative weights found"
@@ -22,3 +26,32 @@ def test_population(tmd_variables):
     assert (
         abs(population / 1e6 / 334.18 - 1) < 0.01
     ), "Population not within 1% of 334.18 million"
+
+
+@pytest.mark.itax
+def test_income_tax():
+
+    def compare(name, act, exp, tol):
+        assert (
+            abs(act / exp - 1) < tol
+        ), f"{name}:act,exp,tol= {act} {exp} {tol}"
+
+    # use national tmd files to compute various 2021 income tax statistics
+    rec = tc.Records.tmd_constructor(
+        data_path=(STORAGE_FOLDER / "output" / "tmd.csv.gz"),
+        weights_path=(STORAGE_FOLDER / "output" / "tmd_weights.csv.gz"),
+        growfactors_path=(STORAGE_FOLDER / "output" / "tmd_growfactors.csv"),
+        exact_calculations=True,
+    )
+    sim = tc.Calculator(policy=tc.Policy(), records=rec)
+    sim.advance_to_year(2021)
+    sim.calc_all()
+    wght = sim.array("s006")
+    agi = sim.array("c00100")
+    itax = sim.array("iitax")
+    # check various income tax statistics
+    compare("wght_sum", wght.sum(), 184e6, 0.01)
+    hiagi = agi >= 1e6
+    compare("wght_sum_hiagi", (wght * hiagi).sum(), 0.875e6, 0.01)
+    compare("wght_itax_sum", (wght * itax).sum(), 1591e9, 0.01)
+    compare("wght_itax_sum_hiagi", ((wght * itax) * hiagi).sum(), 902e9, 0.01)
diff --git a/tests/test_tax_revenue.py b/tests/test_tax_revenue.py
index b2bbc8b5..ea560d13 100644
--- a/tests/test_tax_revenue.py
+++ b/tests/test_tax_revenue.py
@@ -6,11 +6,15 @@
 import taxcalc as tc
 
 
-FIRST_CYR = 2023
+FIRST_CYR = 2021
 LAST_CYR = 2033
 
-RELTOL_ITAX = 0.10
-RELTOL_PTAX = 0.02
+DEFAULT_RELTOL_ITAX = 0.10
+RELTOL_ITAX = {}
+DEFAULT_RELTOL_PTAX = 0.02
+RELTOL_PTAX = {
+    2021: 0.05,
+}
 
 
 DUMP = False  # True implies test always fails with complete output
@@ -60,7 +64,7 @@ def test_tax_revenue(
     emsg = ""
     for year in range(FIRST_CYR, LAST_CYR + 1):
         reldiff = act_itax[year] / exp_itax[year] - 1
-        same = abs(reldiff) < RELTOL_ITAX
+        same = abs(reldiff) < RELTOL_ITAX.get(year, DEFAULT_RELTOL_ITAX)
         if not same or DUMP:
             msg = (
                 f"\nITAX:cyr,act,exp,rdiff= {year} "
@@ -68,7 +72,7 @@ def test_tax_revenue(
             )
             emsg += msg
         reldiff = act_ptax[year] / exp_ptax[year] - 1
-        same = abs(reldiff) < RELTOL_PTAX
+        same = abs(reldiff) < RELTOL_PTAX.get(year, DEFAULT_RELTOL_PTAX)
         if not same or DUMP:
             msg = (
                 f"\nPTAX:cyr,act,exp,rdiff= {year} "