diff --git a/api/src/data_migration/transformation/subtask/transform_agency.py b/api/src/data_migration/transformation/subtask/transform_agency.py
index 921d90169..d5dd11170 100644
--- a/api/src/data_migration/transformation/subtask/transform_agency.py
+++ b/api/src/data_migration/transformation/subtask/transform_agency.py
@@ -272,6 +272,25 @@ def update_agency_download_file_types(
             )
 
 
+class TransformAgencyHierarchy(AbstractTransformSubTask):
+    def __init__(self, task: Task):
+        super().__init__(task)
+
+    def transform_records(self) -> None:
+        agencies = self.db_session.scalars(select(Agency)).all()
+        agency_map = {agency.agency_code: agency for agency in agencies}
+
+        for agency in agencies:
+            top_level_agency_code = self.get_top_level_agency_code(agency.agency_code)
+            if top_level_agency_code and top_level_agency_code in agency_map:
+                agency.top_level_agency = agency_map[top_level_agency_code]
+
+    def get_top_level_agency_code(self, agency_code: str) -> str | None:
+        if "-" not in agency_code:
+            return None
+        return agency_code.split("-")[0]
+
+
 ############################
 # Transformation / utility functions
 ############################
diff --git a/api/src/data_migration/transformation/transform_oracle_data_task.py b/api/src/data_migration/transformation/transform_oracle_data_task.py
index b7ce8e0fd..93b9bf8b4 100644
--- a/api/src/data_migration/transformation/transform_oracle_data_task.py
+++ b/api/src/data_migration/transformation/transform_oracle_data_task.py
@@ -5,7 +5,10 @@
 
 import src.data_migration.transformation.transform_constants as transform_constants
 from src.adapters import db
-from src.data_migration.transformation.subtask.transform_agency import TransformAgency
+from src.data_migration.transformation.subtask.transform_agency import (
+    TransformAgency,
+    TransformAgencyHierarchy,
+)
 from src.data_migration.transformation.subtask.transform_applicant_type import (
     TransformApplicantType,
 )
@@ -81,3 +84,4 @@ def run_task(self) -> None:
 
         if self.transform_config.enable_agency:
             TransformAgency(self).run()
+            TransformAgencyHierarchy(self).run()
diff --git a/api/tests/src/data_migration/transformation/subtask/test_transform_agency.py b/api/tests/src/data_migration/transformation/subtask/test_transform_agency.py
index 4c87247c7..cfa3c6e05 100644
--- a/api/tests/src/data_migration/transformation/subtask/test_transform_agency.py
+++ b/api/tests/src/data_migration/transformation/subtask/test_transform_agency.py
@@ -10,10 +10,12 @@
 from src.data_migration.transformation.subtask.transform_agency import (
     TgroupAgency,
     TransformAgency,
+    TransformAgencyHierarchy,
     apply_updates,
     transform_agency_download_file_types,
     transform_agency_notify,
 )
+from src.db.models.agency_models import Agency
 from tests.src.data_migration.transformation.conftest import (
     BaseTransformTestClass,
     setup_agency,
@@ -22,6 +24,43 @@
 from tests.src.db.models.factories import AgencyFactory
 
 
+class TestTransformAgencyHierarchy(BaseTransformTestClass):
+    @pytest.fixture()
+    def transform_agency_hierarchy(self, transform_oracle_data_task):
+        return TransformAgencyHierarchy(transform_oracle_data_task)
+
+    def test_transform_records(self, db_session, transform_agency_hierarchy):
+        # Create agencies with varying top-level agency codes
+        [
+            AgencyFactory.create(agency_code="DHS"),
+            AgencyFactory.create(agency_code="DHS-ICE"),
+            AgencyFactory.create(agency_code="DHS--ICE"),
+            AgencyFactory.create(agency_code="DHS-ICE-123"),
+            AgencyFactory.create(agency_code="ABC-ICE"),
+        ]
+
+        # Run the transformation
+        transform_agency_hierarchy.transform_records()
+
+        # Fetch the agencies again to verify the changes
+        agency1 = db_session.query(Agency).filter(Agency.agency_code == "DHS").one_or_none()
+        agency2 = db_session.query(Agency).filter(Agency.agency_code == "DHS-ICE").one_or_none()
+        agency3 = db_session.query(Agency).filter(Agency.agency_code == "DHS-ICE-123").one_or_none()
+        agency4 = db_session.query(Agency).filter(Agency.agency_code == "ABC-ICE").one_or_none()
+        agency5 = db_session.query(Agency).filter(Agency.agency_code == "DHS--ICE").one_or_none()
+
+        # Verify that the top-level agencies are set correctly
+        assert agency1.top_level_agency_id is None
+        assert agency2.top_level_agency_id == agency1.agency_id
+        assert agency3.top_level_agency_id == agency1.agency_id
+        assert agency4.top_level_agency_id is None
+        assert agency5.top_level_agency_id == agency1.agency_id
+
+    def test_get_top_level_agency_code(self, transform_agency_hierarchy):
+        assert transform_agency_hierarchy.get_top_level_agency_code("DHS-ICE") == "DHS"
+        assert transform_agency_hierarchy.get_top_level_agency_code("DHS") is None
+
+
 class TestTransformAgency(BaseTransformTestClass):
     @pytest.fixture()
     def transform_agency(self, transform_oracle_data_task):