diff --git a/backend/hitas/services/owner.py b/backend/hitas/services/owner.py
index 29286494b..3439e2f4e 100644
--- a/backend/hitas/services/owner.py
+++ b/backend/hitas/services/owner.py
@@ -101,6 +101,7 @@ def find_owners_with_multiple_ownerships() -> list[OwnershipWithApartmentCount]:
         Ownership.objects.select_related(
             "owner",
             "sale__apartment__building__real_estate__housing_company__postal_code",
+            "sale__apartment__building__real_estate__housing_company",
         )
         .annotate(
             apartment_count=subquery_count(Ownership, "owner"),
diff --git a/backend/hitas/services/reports.py b/backend/hitas/services/reports.py
index dafa52d6f..464c89fb9 100644
--- a/backend/hitas/services/reports.py
+++ b/backend/hitas/services/reports.py
@@ -95,6 +95,10 @@ class MultipleOwnershipReportColumns(NamedTuple):
     apartment_address: str
     postal_code: str
     apartment_count: int | str
+    owner_identifier: str
+    housing_company_name: str
+    housing_company_completion_date: datetime.date | str
+    cost_area: int | str
 
 
 class OwnersByHousingCompanyReportColumns(NamedTuple):
@@ -718,6 +722,10 @@ def build_multiple_ownerships_report_excel(ownerships: list[OwnershipWithApartme
         apartment_address="Asunnon osoite",
         postal_code="Postinumero",
         apartment_count="Omistajan asuntojen lukumäärä",
+        owner_identifier="Omistajan henkilö- tai Y-tunnus",
+        housing_company_name="Yhtiön nimi",
+        housing_company_completion_date="Yhtiön valmistumispäivä",
+        cost_area="Kalleusalue",
     )
     worksheet.append(column_headers)
 
@@ -728,6 +736,10 @@ def build_multiple_ownerships_report_excel(ownerships: list[OwnershipWithApartme
                 apartment_address=ownership.apartment.address,
                 postal_code=ownership.apartment.postal_code.value,
                 apartment_count=ownership.apartment_count,
+                owner_identifier="" if ownership.owner.non_disclosure else ownership.owner.identifier,
+                housing_company_name=ownership.apartment.building.real_estate.housing_company.display_name,
+                housing_company_completion_date=ownership.apartment.building.real_estate.housing_company.completion_date,
+                cost_area=ownership.apartment.postal_code.cost_area,
             )
         )
 
diff --git a/backend/hitas/tests/apis/test_api_reports.py b/backend/hitas/tests/apis/test_api_reports.py
index b46be09d4..7b687ef1a 100644
--- a/backend/hitas/tests/apis/test_api_reports.py
+++ b/backend/hitas/tests/apis/test_api_reports.py
@@ -1427,7 +1427,16 @@ def test__api__multiple_ownerships_report__no_owners(api_client: HitasAPIClient)
     worksheet: Worksheet = workbook.worksheets[0]
 
     assert list(worksheet.values) == [
-        ("Omistajan nimi", "Asunnon osoite", "Postinumero", "Omistajan asuntojen lukumäärä"),
+        (
+            "Omistajan nimi",
+            "Asunnon osoite",
+            "Postinumero",
+            "Omistajan asuntojen lukumäärä",
+            "Omistajan henkilö- tai Y-tunnus",
+            "Yhtiön nimi",
+            "Yhtiön valmistumispäivä",
+            "Kalleusalue",
+        ),
     ]
 
 
@@ -1438,10 +1447,12 @@ def test__api__multiple_ownerships_report__single_owner(api_client: HitasAPIClie
     ownership_1: Ownership = OwnershipFactory.create(
         owner=owner,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00001",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_I,
     )
     ownership_2: Ownership = OwnershipFactory.create(
         owner=owner,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00002",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_II,
     )
 
     url = reverse("hitas:multiple-ownerships-report-list")
@@ -1451,18 +1462,39 @@ def test__api__multiple_ownerships_report__single_owner(api_client: HitasAPIClie
     worksheet: Worksheet = workbook.worksheets[0]
 
     assert list(worksheet.values) == [
-        ("Omistajan nimi", "Asunnon osoite", "Postinumero", "Omistajan asuntojen lukumäärä"),
+        (
+            "Omistajan nimi",
+            "Asunnon osoite",
+            "Postinumero",
+            "Omistajan asuntojen lukumäärä",
+            "Omistajan henkilö- tai Y-tunnus",
+            "Yhtiön nimi",
+            "Yhtiön valmistumispäivä",
+            "Kalleusalue",
+        ),
         (
             Owner.OBFUSCATED_OWNER_NAME if non_disclosure else ownership_1.owner.name,
             ownership_1.apartment.address,
             ownership_1.apartment.postal_code.value,
             2,
+            None if non_disclosure else ownership_1.owner.identifier,
+            ownership_1.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_1.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_1.apartment.postal_code.cost_area,
         ),
         (
             Owner.OBFUSCATED_OWNER_NAME if non_disclosure else ownership_2.owner.name,
             ownership_2.apartment.address,
             ownership_2.apartment.postal_code.value,
             2,
+            None if non_disclosure else ownership_2.owner.identifier,
+            ownership_2.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_2.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_2.apartment.postal_code.cost_area,
         ),
     ]
 
@@ -1473,24 +1505,29 @@ def test__api__multiple_ownerships_report__multiple_owners(api_client: HitasAPIC
     ownership_1: Ownership = OwnershipFactory.create(
         owner=owner_1,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00001",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_I,
     )
     ownership_2: Ownership = OwnershipFactory.create(
         owner=owner_1,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00002",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_I,
     )
 
     owner_2: Owner = OwnerFactory.create(name="Owner 2", non_disclosure=True)
     ownership_3: Ownership = OwnershipFactory.create(
         owner=owner_2,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00001",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_I,
     )
     ownership_4: Ownership = OwnershipFactory.create(
         owner=owner_2,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00002",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_I,
     )
     ownership_5: Ownership = OwnershipFactory.create(
         owner=owner_2,
         sale__apartment__building__real_estate__housing_company__postal_code__value="00003",
+        sale__apartment__building__real_estate__housing_company__hitas_type=HitasType.NEW_HITAS_I,
     )
 
     url = reverse("hitas:multiple-ownerships-report-list")
@@ -1500,12 +1537,76 @@ def test__api__multiple_ownerships_report__multiple_owners(api_client: HitasAPIC
     worksheet: Worksheet = workbook.worksheets[0]
 
     assert list(worksheet.values) == [
-        ("Omistajan nimi", "Asunnon osoite", "Postinumero", "Omistajan asuntojen lukumäärä"),
-        (ownership_1.owner.name, ownership_1.apartment.address, ownership_1.apartment.postal_code.value, 2),
-        (ownership_2.owner.name, ownership_2.apartment.address, ownership_2.apartment.postal_code.value, 2),
-        (Owner.OBFUSCATED_OWNER_NAME, ownership_3.apartment.address, ownership_3.apartment.postal_code.value, 3),
-        (Owner.OBFUSCATED_OWNER_NAME, ownership_4.apartment.address, ownership_4.apartment.postal_code.value, 3),
-        (Owner.OBFUSCATED_OWNER_NAME, ownership_5.apartment.address, ownership_5.apartment.postal_code.value, 3),
+        (
+            "Omistajan nimi",
+            "Asunnon osoite",
+            "Postinumero",
+            "Omistajan asuntojen lukumäärä",
+            "Omistajan henkilö- tai Y-tunnus",
+            "Yhtiön nimi",
+            "Yhtiön valmistumispäivä",
+            "Kalleusalue",
+        ),
+        (
+            ownership_1.owner.name,
+            ownership_1.apartment.address,
+            ownership_1.apartment.postal_code.value,
+            2,
+            None if ownership_1.owner.non_disclosure else ownership_1.owner.identifier,
+            ownership_1.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_1.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_1.apartment.postal_code.cost_area,
+        ),
+        (
+            ownership_2.owner.name,
+            ownership_2.apartment.address,
+            ownership_2.apartment.postal_code.value,
+            2,
+            None if ownership_2.owner.non_disclosure else ownership_2.owner.identifier,
+            ownership_2.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_2.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_2.apartment.postal_code.cost_area,
+        ),
+        (
+            Owner.OBFUSCATED_OWNER_NAME,
+            ownership_3.apartment.address,
+            ownership_3.apartment.postal_code.value,
+            3,
+            None if ownership_3.owner.non_disclosure else ownership_3.owner.identifier,
+            ownership_3.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_3.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_3.apartment.postal_code.cost_area,
+        ),
+        (
+            Owner.OBFUSCATED_OWNER_NAME,
+            ownership_4.apartment.address,
+            ownership_4.apartment.postal_code.value,
+            3,
+            None if ownership_4.owner.non_disclosure else ownership_4.owner.identifier,
+            ownership_4.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_4.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_4.apartment.postal_code.cost_area,
+        ),
+        (
+            Owner.OBFUSCATED_OWNER_NAME,
+            ownership_5.apartment.address,
+            ownership_5.apartment.postal_code.value,
+            3,
+            None if ownership_5.owner.non_disclosure else ownership_5.owner.identifier,
+            ownership_5.apartment.building.real_estate.housing_company.display_name,
+            datetime.datetime.combine(
+                ownership_5.apartment.building.real_estate.housing_company.completion_date, datetime.datetime.min.time()
+            ),
+            ownership_5.apartment.postal_code.cost_area,
+        ),
     ]