diff --git a/changelog_entry.yaml b/changelog_entry.yaml
index e69de29b..a71cd5ed 100644
--- a/changelog_entry.yaml
+++ b/changelog_entry.yaml
@@ -0,0 +1,4 @@
+- bump: patch
+  changes:
+    fixed:
+    - Fix bug affecting microsimulation runs in countries which use automatic period adjustments.
diff --git a/policyengine_core/simulations/simulation.py b/policyengine_core/simulations/simulation.py
index 123a1be8..d0cd74ab 100644
--- a/policyengine_core/simulations/simulation.py
+++ b/policyengine_core/simulations/simulation.py
@@ -474,12 +474,12 @@ def _calculate(
         if variable.definition_period == MONTH and period.unit == YEAR:
             if variable.quantity_type == QuantityType.STOCK:
                 contained_months = period.get_subperiods(MONTH)
-                return self.calculate(variable_name, contained_months[-1])
+                return self._calculate(variable_name, contained_months[-1])
             else:
                 return self.calculate_add(variable_name, period)
         elif variable.definition_period == YEAR and period.unit == MONTH:
             if variable.quantity_type == QuantityType.STOCK:
-                return self.calculate(variable_name, period.this_year)
+                return self._calculate(variable_name, period.this_year)
             else:
                 return self.calculate_divide(variable_name, period)