diff --git a/README.md b/README.md
index 6e294b5..bc0bff7 100644
--- a/README.md
+++ b/README.md
@@ -223,6 +223,9 @@ docker compose -f ../docs/dev/docker-compose.yml down -v     # полный сб
 `src/domain/policy.py`: пользователь головного офиса видит всё, пользователь филиала — ГК своего филиала, их ЮЛ и
 ГСК/ГСЗ и монозаёмщиков своего филиала. Объект вне видимости — **404 с тем же телом, что у несуществующего** (не 403).
 
+Филиал в ответах ЮЛ и ГК приходит объектом рядом с `*_id`: `regional_office` (ЮЛ, их история) и `base_regional_office`
+(ГК, их история) — `{id, name, is_head_office}` или `null`; неактивный филиал тоже отдаётся (имя нужно для истории).
+
 | Метод и путь | Право | Что делает |
 |---|---|---|
 | `GET /directories/regional-offices` | `DIRECTORY_VIEW` | филиалы (включая Головной офис) |
diff --git a/api/src/api/endpoints/directories/company_groups.py b/api/src/api/endpoints/directories/company_groups.py
index 4aba2f1..454ea03 100644
--- a/api/src/api/endpoints/directories/company_groups.py
+++ b/api/src/api/endpoints/directories/company_groups.py
@@ -10,7 +10,6 @@ from fastapi import APIRouter, Depends, Query, status
 
 from src.api.dependencies.auth import require
 from src.api.dependencies.directories import CompanyGroupServiceDep
-from src.models.directories import CompanyGroup
 from src.schemas.common import Page, PageParams
 from src.schemas.directories import (
     CompanyGroupCreate,
@@ -30,12 +29,6 @@ class CompanyGroupListQuery(CompanyGroupFilter, PageParams):
     """Query списка ГК: фильтры и пагинация одной моделью (FastAPI поддерживает одну Query-модель на маршрут)."""
 
 
-def _out(group: CompanyGroup, legal_entities_count: int) -> CompanyGroupOut:
-    out = CompanyGroupOut.model_validate(group)
-    out.legal_entities_count = legal_entities_count
-    return out
-
-
 @router.get("", response_model=Page[CompanyGroupOut], dependencies=VIEW, summary="Список ГК")
 async def list_company_groups(
     service: CompanyGroupServiceDep,
@@ -44,9 +37,7 @@ async def list_company_groups(
     """Видимые ГК: поиск `q` по name/crm_id/code, фильтр `is_archived`, пагинация, сортировка по имени."""
     page = PageParams(limit=query.limit, offset=query.offset)
     rows, total = await service.page(CompanyGroupFilter(q=query.q, is_archived=query.is_archived), page)
-    return Page[CompanyGroupOut](
-        items=[_out(group, count) for group, count in rows], total=total, limit=page.limit, offset=page.offset
-    )
+    return Page[CompanyGroupOut](items=await service.to_outs(rows), total=total, limit=page.limit, offset=page.offset)
 
 
 @router.post(
@@ -54,13 +45,13 @@ async def list_company_groups(
 )
 async def create_company_group(data: CompanyGroupCreate, service: CompanyGroupServiceDep) -> CompanyGroupOut:
     """Создаёт ГК с кодом `GK-NNNNNN`; без филиала пользователь филиала закрепляет ГК за своим."""
-    return _out(await service.create(data), 0)
+    return await service.to_out(await service.create(data), 0)
 
 
 @router.get("/{group_id}", response_model=CompanyGroupOut, dependencies=VIEW, summary="Карточка ГК")
 async def get_company_group(group_id: uuid.UUID, service: CompanyGroupServiceDep) -> CompanyGroupOut:
     group = await service.get(group_id)
-    return _out(group, await service.legal_entities_count(group.id))
+    return await service.to_out(group, await service.legal_entities_count(group.id))
 
 
 @router.patch("/{group_id}", response_model=CompanyGroupOut, dependencies=EDIT, summary="Изменить ГК")
@@ -69,19 +60,19 @@ async def update_company_group(
 ) -> CompanyGroupOut:
     """Меняет `name`/`crm_id`/`base_regional_office_id`; прежние значения уходят в историю."""
     group = await service.update(group_id, data)
-    return _out(group, await service.legal_entities_count(group.id))
+    return await service.to_out(group, await service.legal_entities_count(group.id))
 
 
 @router.post("/{group_id}/archive", response_model=CompanyGroupOut, dependencies=EDIT, summary="Архивировать ГК")
 async def archive_company_group(group_id: uuid.UUID, service: CompanyGroupServiceDep) -> CompanyGroupOut:
     group = await service.set_archived(group_id, True)  # noqa: FBT003
-    return _out(group, await service.legal_entities_count(group.id))
+    return await service.to_out(group, await service.legal_entities_count(group.id))
 
 
 @router.post("/{group_id}/unarchive", response_model=CompanyGroupOut, dependencies=EDIT, summary="Вернуть ГК из архива")
 async def unarchive_company_group(group_id: uuid.UUID, service: CompanyGroupServiceDep) -> CompanyGroupOut:
     group = await service.set_archived(group_id, False)  # noqa: FBT003
-    return _out(group, await service.legal_entities_count(group.id))
+    return await service.to_out(group, await service.legal_entities_count(group.id))
 
 
 @router.get(
@@ -91,4 +82,4 @@ async def unarchive_company_group(group_id: uuid.UUID, service: CompanyGroupServ
     summary="История ГК (новые первыми)",
 )
 async def company_group_history(group_id: uuid.UUID, service: CompanyGroupServiceDep) -> list[CompanyGroupHistoryOut]:
-    return [CompanyGroupHistoryOut.model_validate(row) for row in await service.history(group_id)]
+    return await service.history(group_id)
diff --git a/api/src/api/endpoints/directories/legal_entities.py b/api/src/api/endpoints/directories/legal_entities.py
index eda1317..4cf3952 100644
--- a/api/src/api/endpoints/directories/legal_entities.py
+++ b/api/src/api/endpoints/directories/legal_entities.py
@@ -11,7 +11,6 @@ from fastapi import APIRouter, Depends, Query, status
 
 from src.api.dependencies.auth import require
 from src.api.dependencies.directories import AliasServiceDep, LegalEntityServiceDep
-from src.models.directories import LegalEntity
 from src.schemas.common import Page, PageParams
 from src.schemas.directories import (
     AliasCreate,
@@ -37,13 +36,6 @@ class LegalEntityListQuery(LegalEntityFilter, PageParams):
     """Query списка ЮЛ: фильтры и пагинация одной моделью (FastAPI поддерживает одну Query-модель на маршрут)."""
 
 
-def _out(entity: LegalEntity, documents_count: int) -> LegalEntityOut:
-    """Конвертирует ORM ЮЛ в LegalEntityOut с подсчитанным количеством документов."""
-    out = LegalEntityOut.model_validate(entity)
-    out.documents_count = documents_count
-    return out
-
-
 @router.get("", response_model=Page[LegalEntityOut], dependencies=VIEW, summary="Список ЮЛ/ИП")
 async def list_legal_entities(
     service: LegalEntityServiceDep,
@@ -56,7 +48,7 @@ async def list_legal_entities(
     entity_ids = [entity.id for entity in items]
     counts = await service.documents_count_by_entities(entity_ids)
     return Page[LegalEntityOut](
-        items=[_out(entity, counts.get(entity.id, 0)) for entity in items],
+        items=await service.to_outs(items, counts),
         total=total,
         limit=page.limit,
         offset=page.offset,
@@ -69,7 +61,7 @@ async def list_legal_entities(
 async def create_legal_entity(data: LegalEntityCreate, service: LegalEntityServiceDep) -> LegalEntityOut:
     """Создаёт ЮЛ/ИП; без `company_group_id` — монозаёмщик; ИНН: ЮЛ — 10 цифр, ИП — 12."""
     entity = await service.create(data)
-    return _out(entity, 0)
+    return await service.to_out(entity, 0)
 
 
 @router.get("/{entity_id}", response_model=LegalEntityDetail, dependencies=VIEW, summary="Карточка ЮЛ/ИП")
@@ -86,7 +78,7 @@ async def update_legal_entity(
 ) -> LegalEntityOut:
     """Меняет `name`/`entity_type`/`crm_id`/`regional_office_id`; прежние значения уходят в историю (`UPDATE`)."""
     entity = await service.update(entity_id, data)
-    return _out(entity, await service.documents_count(entity_id))
+    return await service.to_out(entity, await service.documents_count(entity_id))
 
 
 @router.post("/{entity_id}/move", response_model=LegalEntityOut, dependencies=EDIT, summary="Перевести ЮЛ в другую ГК")
@@ -95,7 +87,7 @@ async def move_legal_entity(
 ) -> LegalEntityOut:
     """Переводит ЮЛ в другую ГК с `effective_date` (≥ сегодня); текущие членства ГСК/ГСЗ закрываются."""
     entity = await service.move(entity_id, data)
-    return _out(entity, await service.documents_count(entity_id))
+    return await service.to_out(entity, await service.documents_count(entity_id))
 
 
 @router.post(
@@ -107,7 +99,7 @@ async def withdraw_legal_entity(
     """`CLOSE` — закрытие (`close_date = effective_date`), `REMOVE_FROM_GROUP` — вывод; ГК снимается, членства
     закрываются."""
     entity = await service.withdraw(entity_id, data)
-    return _out(entity, await service.documents_count(entity_id))
+    return await service.to_out(entity, await service.documents_count(entity_id))
 
 
 @router.get(
@@ -117,7 +109,7 @@ async def withdraw_legal_entity(
     summary="История ЮЛ/ИП (новые первыми)",
 )
 async def legal_entity_history(entity_id: uuid.UUID, service: LegalEntityServiceDep) -> list[LegalEntityHistoryOut]:
-    return [LegalEntityHistoryOut.model_validate(row) for row in await service.history(entity_id)]
+    return await service.history(entity_id)
 
 
 @router.post(
diff --git a/api/src/repositories/directories.py b/api/src/repositories/directories.py
index f60d681..98bbd26 100644
--- a/api/src/repositories/directories.py
+++ b/api/src/repositories/directories.py
@@ -7,6 +7,7 @@ SQL без бизнес-правил; видимость — `src.domain.policy`
 
 import datetime
 import uuid
+from collections.abc import Iterable
 from typing import Any
 
 from sqlalchemy import Select, Sequence, and_, delete, func, or_, select
@@ -415,6 +416,17 @@ async def get_regional_office(session: AsyncSession, office_id: uuid.UUID) -> Re
     return await session.get(RegionalOffice, office_id)
 
 
+async def regional_offices_by_ids(
+    session: AsyncSession, office_ids: Iterable[uuid.UUID | None]
+) -> dict[uuid.UUID, RegionalOffice]:
+    """Филиалы по набору id одним запросом (включая неактивные); `None` и дубли игнорируются."""
+    ids = {office_id for office_id in office_ids if office_id is not None}
+    if not ids:
+        return {}
+    rows = (await session.execute(select(RegionalOffice).where(RegionalOffice.id.in_(ids)))).scalars().all()
+    return {office.id: office for office in rows}
+
+
 async def list_regional_offices(session: AsyncSession) -> list[RegionalOffice]:
     """Все филиалы по имени."""
     return list((await session.execute(select(RegionalOffice).order_by(RegionalOffice.name))).scalars().all())
diff --git a/api/src/schemas/directories.py b/api/src/schemas/directories.py
index a731caa..49ac07e 100644
--- a/api/src/schemas/directories.py
+++ b/api/src/schemas/directories.py
@@ -99,6 +99,9 @@ class CompanyGroupOut(BaseModel):
     crm_id: str | None
     name: str
     base_regional_office_id: uuid.UUID | None
+    base_regional_office: RegionalOfficeBrief | None = (
+        None  # объект филиала; неактивный тоже отдаётся (имя для истории)
+    )
     is_archived: bool
     valid_from: datetime.datetime
     legal_entities_count: int = 0
@@ -115,6 +118,7 @@ class CompanyGroupHistoryOut(BaseModel):
     crm_id: str | None
     name: str | None
     base_regional_office_id: uuid.UUID | None
+    base_regional_office: RegionalOfficeBrief | None = None  # филиал снимка (в history нет FK — батч по id)
     valid_from: datetime.datetime | None
     valid_to: datetime.datetime | None
     changed_by: uuid.UUID | None
@@ -222,6 +226,7 @@ class LegalEntityOut(BaseModel):
     name: str
     company_group_id: uuid.UUID | None
     regional_office_id: uuid.UUID | None
+    regional_office: RegionalOfficeBrief | None = None  # объект филиала; неактивный тоже отдаётся
     close_date: datetime.date | None
     valid_from: datetime.datetime
     created_at: datetime.datetime | None
@@ -285,6 +290,7 @@ class LegalEntityHistoryOut(BaseModel):
     name: str | None
     company_group_id: uuid.UUID | None
     regional_office_id: uuid.UUID | None
+    regional_office: RegionalOfficeBrief | None = None  # филиал снимка (в history нет FK — батч по id)
     close_date: datetime.date | None
     event_type: LeHistoryEvent | None
     effective_date: datetime.date | None
diff --git a/api/src/services/company_groups.py b/api/src/services/company_groups.py
index 868671e..e523e30 100644
--- a/api/src/services/company_groups.py
+++ b/api/src/services/company_groups.py
@@ -6,7 +6,7 @@
 
 import datetime
 import uuid
-from collections.abc import Mapping
+from collections.abc import Iterable, Mapping, Sequence
 from typing import Any
 
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -19,7 +19,14 @@ from src.models.directories import COMPANY_GROUP_CODE_SEQ, CompanyGroup, Company
 from src.models.enums import AuditAction, AuditSection
 from src.repositories import directories as repo
 from src.schemas.common import PageParams
-from src.schemas.directories import CompanyGroupCreate, CompanyGroupFilter, CompanyGroupUpdate
+from src.schemas.directories import (
+    CompanyGroupCreate,
+    CompanyGroupFilter,
+    CompanyGroupHistoryOut,
+    CompanyGroupOut,
+    CompanyGroupUpdate,
+    RegionalOfficeBrief,
+)
 
 COMPANY_GROUP_NOT_FOUND = "ГК не найдена"  # одинаково для чужой и несуществующей (spec directory-policy)
 COMPANY_GROUP_CODE_PREFIX = "GK"
@@ -149,14 +156,43 @@ class CompanyGroupService:
             raise NotFoundError(COMPANY_GROUP_NOT_FOUND)
         return group
 
+    async def offices_by_ids(self, office_ids: Iterable[uuid.UUID | None]) -> dict[uuid.UUID, RegionalOfficeBrief]:
+        """Филиалы (в т.ч. неактивные) по набору id — один запрос на набор, без N+1."""
+        offices = await repo.regional_offices_by_ids(self._session, office_ids)
+        return {office_id: RegionalOfficeBrief.model_validate(office) for office_id, office in offices.items()}
+
+    async def to_out(self, group: CompanyGroup, legal_entities_count: int) -> CompanyGroupOut:
+        """Ответ по одной ГК с объектом филиала."""
+        return (await self.to_outs([(group, legal_entities_count)]))[0]
+
+    async def to_outs(self, rows: Sequence[tuple[CompanyGroup, int]]) -> list[CompanyGroupOut]:
+        """Ответы по набору ГК; филиалы — одним батч-запросом."""
+        offices = await self.offices_by_ids(group.base_regional_office_id for group, _ in rows)
+        result: list[CompanyGroupOut] = []
+        for group, count in rows:
+            out = CompanyGroupOut.model_validate(group)
+            out.legal_entities_count = count
+            out.base_regional_office = (
+                offices.get(group.base_regional_office_id) if group.base_regional_office_id else None
+            )
+            result.append(out)
+        return result
+
     async def legal_entities_count(self, group_id: uuid.UUID) -> int:
         """Число ЮЛ ГК (для карточки)."""
         return await repo.count_legal_entities(self._session, group_id)
 
-    async def history(self, group_id: uuid.UUID) -> list[CompanyGroupHistory]:
-        """Снимки ГК по убыванию `valid_from`; видимость проверяется как для карточки."""
+    async def history(self, group_id: uuid.UUID) -> list[CompanyGroupHistoryOut]:
+        """Снимки ГК по убыванию `valid_from`; видимость — как для карточки; филиалы снимков — одним батчем."""
         group = await self.get(group_id)
-        return await repo.list_company_group_history(self._session, group.id)
+        rows = await repo.list_company_group_history(self._session, group.id)
+        offices = await self.offices_by_ids(row.base_regional_office_id for row in rows)
+        result: list[CompanyGroupHistoryOut] = []
+        for row in rows:
+            out = CompanyGroupHistoryOut.model_validate(row)
+            out.base_regional_office = offices.get(row.base_regional_office_id) if row.base_regional_office_id else None
+            result.append(out)
+        return result
 
     async def page(self, params: CompanyGroupFilter, page: PageParams) -> tuple[list[tuple[CompanyGroup, int]], int]:
         """Страница видимых ГК с числом ЮЛ и общее число по фильтру."""
diff --git a/api/src/services/legal_entities.py b/api/src/services/legal_entities.py
index ffaa497..e5bab0b 100644
--- a/api/src/services/legal_entities.py
+++ b/api/src/services/legal_entities.py
@@ -8,7 +8,7 @@
 
 import datetime
 import uuid
-from collections.abc import Mapping
+from collections.abc import Iterable, Mapping, Sequence
 from typing import Any
 
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -27,10 +27,13 @@ from src.schemas.directories import (
     LegalEntityCreate,
     LegalEntityDetail,
     LegalEntityFilter,
+    LegalEntityHistoryOut,
     LegalEntityMove,
+    LegalEntityOut,
     LegalEntityUpdate,
     LegalEntityWithdraw,
     MembershipOut,
+    RegionalOfficeBrief,
 )
 from src.services.company_groups import COMPANY_GROUP_NOT_FOUND
 
@@ -243,6 +246,7 @@ class LegalEntityService:
         """Карточка: ЮЛ, текущие членства ГСК/ГСЗ и алиасы; невидимое и несуществующее — один и тот же 404."""
         entity = await self._get_entity(entity_id)
         detail = LegalEntityDetail.model_validate(entity)
+        detail.regional_office = (await self.offices_by_ids([entity.regional_office_id])).get(entity.regional_office_id)
         detail.memberships = [
             MembershipOut(
                 related_group_id=group.id,
@@ -256,10 +260,39 @@ class LegalEntityService:
         detail.aliases = [AliasOut.model_validate(alias) for alias in await repo.list_aliases(self._session, entity.id)]
         return detail
 
-    async def history(self, entity_id: uuid.UUID) -> list[LegalEntityHistory]:
-        """Снимки ЮЛ по убыванию `valid_from` (R-3); видимость — как для карточки."""
+    async def history(self, entity_id: uuid.UUID) -> list[LegalEntityHistoryOut]:
+        """Снимки ЮЛ по убыванию `valid_from` (R-3); видимость — как для карточки; филиалы снимков — одним батчем."""
         entity = await self._get_entity(entity_id)
-        return await repo.list_legal_entity_history(self._session, entity.id)
+        rows = await repo.list_legal_entity_history(self._session, entity.id)
+        offices = await self.offices_by_ids(row.regional_office_id for row in rows)
+        result: list[LegalEntityHistoryOut] = []
+        for row in rows:
+            out = LegalEntityHistoryOut.model_validate(row)
+            out.regional_office = offices.get(row.regional_office_id)
+            result.append(out)
+        return result
+
+    async def offices_by_ids(
+        self, office_ids: Iterable[uuid.UUID | None]
+    ) -> dict[uuid.UUID | None, RegionalOfficeBrief]:
+        """Филиалы (в т.ч. неактивные) по набору id — один запрос на набор, без N+1."""
+        offices = await repo.regional_offices_by_ids(self._session, office_ids)
+        return {office_id: RegionalOfficeBrief.model_validate(office) for office_id, office in offices.items()}
+
+    async def to_outs(self, entities: Sequence[LegalEntity], counts: Mapping[uuid.UUID, int]) -> list[LegalEntityOut]:
+        """Ответы по набору ЮЛ с числом документов; филиалы — одним батч-запросом."""
+        offices = await self.offices_by_ids(entity.regional_office_id for entity in entities)
+        result: list[LegalEntityOut] = []
+        for entity in entities:
+            out = LegalEntityOut.model_validate(entity)
+            out.documents_count = counts.get(entity.id, 0)
+            out.regional_office = offices.get(entity.regional_office_id)
+            result.append(out)
+        return result
+
+    async def to_out(self, entity: LegalEntity, documents_count: int) -> LegalEntityOut:
+        """Ответ по одному ЮЛ с объектом филиала."""
+        return (await self.to_outs([entity], {entity.id: documents_count}))[0]
 
     async def page(self, flt: LegalEntityFilter, page: PageParams) -> tuple[list[LegalEntity], int]:
         """Страница видимых ЮЛ и общее число по фильтру."""
diff --git a/api/tests/test_api_company_groups.py b/api/tests/test_api_company_groups.py
index 2bf27dc..166990e 100644
--- a/api/tests/test_api_company_groups.py
+++ b/api/tests/test_api_company_groups.py
@@ -265,6 +265,7 @@ async def test_history_is_ordered_by_valid_from_desc(auth_client: AuthClientFact
         "crm_id",
         "name",
         "base_regional_office_id",
+        "base_regional_office",
         "valid_from",
         "valid_to",
         "changed_by",
diff --git a/api/tests/test_api_legal_entities.py b/api/tests/test_api_legal_entities.py
index f7edaff..d8f2899 100644
--- a/api/tests/test_api_legal_entities.py
+++ b/api/tests/test_api_legal_entities.py
@@ -388,6 +388,7 @@ async def test_patch_writes_update_snapshot_and_audit(auth_client: AuthClientFac
         "company_group_id",
         "regional_office_id",
         "close_date",
+        "regional_office",
         "event_type",
         "effective_date",
         "valid_from",
diff --git a/api/tests/test_api_regional_office_object.py b/api/tests/test_api_regional_office_object.py
new file mode 100644
index 0000000..2709450
--- /dev/null
+++ b/api/tests/test_api_regional_office_object.py
@@ -0,0 +1,205 @@
+"""Основной РФ объектом в ответах ЮЛ и ГК (arm-core#47): `regional_office` / `base_regional_office`, без N+1."""
+
+import datetime
+from collections.abc import Iterator
+from typing import Any
+
+import pytest
+from sqlalchemy import event
+from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession
+
+from src.common.clock import moscow_date
+from src.models.directories import CompanyGroupHistory, LegalEntityHistory
+from tests.conftest import AuthClientFactory
+from tests.factories import make_company_group, make_legal_entity, make_regional_office
+
+HTTP_OK = 200
+HTTP_CREATED = 201
+SMALL = 2
+ENTITIES = "/directories/legal-entities"
+GROUPS = "/directories/company-groups"
+KA_GO = "ka_go@armka.local"
+
+
+def _brief(office: Any) -> dict[str, Any]:
+    return {"id": str(office.id), "name": office.name, "is_head_office": office.is_head_office}
+
+
+@pytest.fixture
+def sql_log(db_engine: AsyncEngine) -> Iterator[list[str]]:
+    statements: list[str] = []
+
+    def record(_conn: Any, _cursor: Any, statement: str, *_rest: Any) -> None:
+        statements.append(statement)
+
+    event.listen(db_engine.sync_engine, "before_cursor_execute", record)
+    try:
+        yield statements
+    finally:
+        event.remove(db_engine.sync_engine, "before_cursor_execute", record)
+
+
+def _office_selects(statements: list[str]) -> int:
+    return sum(1 for s in statements if s.lstrip().upper().startswith("SELECT") and "FROM dkb.regional_office" in s)
+
+
+@pytest.mark.integration
+async def test_legal_entity_responses_carry_office_object(auth_client: AuthClientFactory, seeded: AsyncSession) -> None:
+    office = await make_regional_office(seeded, name="Филиал Объект")
+    other = await make_regional_office(seeded, name="Филиал Другой")
+    group = await make_company_group(seeded, name="ГК Объект", office=office)
+    entity = await make_legal_entity(seeded, name="ООО Объект", group=group, office=office)
+    new_group = await make_company_group(seeded, name="ГК Новая цель", office=other)
+    mono = await make_legal_entity(seeded, name="ООО Без филиала")
+    client = await auth_client(KA_GO)
+
+    card = (await client.get(f"{ENTITIES}/{entity.id}")).json()
+    assert card["regional_office"] == _brief(office)
+    assert card["regional_office_id"] == str(office.id)
+    no_office = (await client.get(f"{ENTITIES}/{mono.id}")).json()
+    assert no_office["regional_office"] is None and no_office["regional_office_id"] is None
+
+    listing = (await client.get(ENTITIES, params={"q": "ООО"})).json()["items"]
+    by_name = {item["name"]: item for item in listing}
+    assert by_name["ООО Объект"]["regional_office"] == _brief(office)
+    assert by_name["ООО Без филиала"]["regional_office"] is None
+
+    patched = await client.patch(f"{ENTITIES}/{entity.id}", json={"regional_office_id": str(other.id)})
+    assert patched.status_code == HTTP_OK, patched.text
+    assert patched.json()["regional_office"] == _brief(other)
+
+    history = (await client.get(f"{ENTITIES}/{entity.id}/history")).json()
+    assert history[0]["regional_office_id"] == str(office.id)
+    assert history[0]["regional_office"] == _brief(office)  # филиал снимка, не текущий
+
+    move = await client.post(
+        f"{ENTITIES}/{entity.id}/move",
+        json={
+            "company_group_id": str(new_group.id),
+            "effective_date": moscow_date(datetime.datetime.now(datetime.UTC)).isoformat(),
+        },
+    )
+    assert move.status_code == HTTP_OK, move.text
+    assert move.json()["regional_office"] == _brief(other)
+    withdraw = await client.post(
+        f"{ENTITIES}/{entity.id}/withdraw",
+        json={
+            "event": "REMOVE_FROM_GROUP",
+            "effective_date": moscow_date(datetime.datetime.now(datetime.UTC)).isoformat(),
+        },
+    )
+    assert withdraw.status_code == HTTP_OK, withdraw.text
+    assert withdraw.json()["regional_office"] == _brief(other)
+
+    created = await client.post(
+        ENTITIES,
+        json={"inn": "7701234567", "name": "ООО Новое", "entity_type": "ЮЛ", "regional_office_id": str(office.id)},
+    )
+    assert created.status_code == HTTP_CREATED, created.text
+    assert created.json()["regional_office"] == _brief(office)
+
+
+@pytest.mark.integration
+async def test_inactive_office_is_still_returned(auth_client: AuthClientFactory, seeded: AsyncSession) -> None:
+    office = await make_regional_office(seeded, name="Филиал Закрытый")
+    office.is_active = False
+    await seeded.flush()
+    group = await make_company_group(seeded, name="ГК Закрытая", office=office)
+    entity = await make_legal_entity(seeded, name="ООО Закрытое", group=group)
+    client = await auth_client(KA_GO)
+
+    assert (await client.get(f"{ENTITIES}/{entity.id}")).json()["regional_office"] == _brief(office)
+    assert (await client.get(f"{GROUPS}/{group.id}")).json()["base_regional_office"] == _brief(office)
+
+
+@pytest.mark.integration
+async def test_company_group_responses_carry_office_object(
+    auth_client: AuthClientFactory, seeded: AsyncSession
+) -> None:
+    office = await make_regional_office(seeded, name="Филиал ГК")
+    other = await make_regional_office(seeded, name="Филиал ГК 2")
+    group = await make_company_group(seeded, name="ГК Один", office=office)
+    bare = await make_company_group(seeded, name="ГК Два")
+    client = await auth_client(KA_GO)
+
+    card = (await client.get(f"{GROUPS}/{group.id}")).json()
+    assert card["base_regional_office"] == _brief(office) and card["base_regional_office_id"] == str(office.id)
+    assert (await client.get(f"{GROUPS}/{bare.id}")).json()["base_regional_office"] is None
+    items = {i["name"]: i for i in (await client.get(GROUPS, params={"q": "ГК "})).json()["items"]}
+    assert items["ГК Один"]["base_regional_office"] == _brief(office)
+    assert items["ГК Два"]["base_regional_office"] is None
+
+    patched = await client.patch(f"{GROUPS}/{group.id}", json={"base_regional_office_id": str(other.id)})
+    assert patched.status_code == HTTP_OK, patched.text
+    assert patched.json()["base_regional_office"] == _brief(other)
+    for action in ("archive", "unarchive"):
+        resp = await client.post(f"{GROUPS}/{group.id}/{action}")
+        assert resp.json()["base_regional_office"] == _brief(other)
+    created = await client.post(GROUPS, json={"name": "ГК Новая", "base_regional_office_id": str(office.id)})
+    assert created.status_code == HTTP_CREATED, created.text
+    assert created.json()["base_regional_office"] == _brief(office)
+
+    history = (await client.get(f"{GROUPS}/{group.id}/history")).json()
+    assert history[0]["base_regional_office_id"] == str(office.id)
+    assert history[0]["base_regional_office"] == _brief(office)
+
+
+@pytest.mark.integration
+async def test_history_loads_offices_in_one_query(
+    auth_client: AuthClientFactory, seeded: AsyncSession, sql_log: list[str]
+) -> None:
+    offices = [await make_regional_office(seeded, name=f"Филиал история {n}") for n in range(4)]
+    group = await make_company_group(seeded, name="ГК История", office=offices[0])
+    entity = await make_legal_entity(seeded, name="ООО История", group=group, office=offices[0])
+    now = datetime.datetime.now(datetime.UTC)
+    for n, office in enumerate(offices):
+        stamp = now - datetime.timedelta(days=n + 1)
+        seeded.add(
+            CompanyGroupHistory(
+                company_group_id=group.id, name="x", base_regional_office_id=office.id, valid_from=stamp, valid_to=now
+            )
+        )
+        seeded.add(
+            LegalEntityHistory(
+                legal_entity_id=entity.id, name="x", regional_office_id=office.id, valid_from=stamp, valid_to=now
+            )
+        )
+    await seeded.flush()
+    client = await auth_client(KA_GO)
+
+    sql_log.clear()
+    rows = (await client.get(f"{ENTITIES}/{entity.id}/history")).json()
+    assert {r["regional_office"]["name"] for r in rows} == {o.name for o in offices}
+    assert _office_selects(sql_log) == 1
+    sql_log.clear()
+    rows = (await client.get(f"{GROUPS}/{group.id}/history")).json()
+    assert {r["base_regional_office"]["name"] for r in rows} == {o.name for o in offices}
+    assert _office_selects(sql_log) == 1
+
+
+@pytest.mark.integration
+async def test_lists_do_not_grow_queries_with_rows(
+    auth_client: AuthClientFactory, seeded: AsyncSession, sql_log: list[str]
+) -> None:
+    client = await auth_client(KA_GO)
+    await client.get(ENTITIES)  # прогрев (первый запрос сессии тянет лишнее)
+    await client.get(GROUPS)
+    total_before: dict[str, int] = {}
+    for size in (2, 12):
+        for n in range(size):
+            office = await make_regional_office(seeded, name=f"Филиал список {size}-{n}")
+            group = await make_company_group(seeded, name=f"ГК список {size}-{n}", office=office)
+            await make_legal_entity(seeded, name=f"ООО список {size}-{n}", group=group, office=office)
+        for url, key in ((ENTITIES, "regional_office"), (GROUPS, "base_regional_office")):
+            sql_log.clear()
+            response = await client.get(url, params={"q": "список", "limit": 200})
+            assert response.status_code == HTTP_OK, response.text
+            items = response.json()["items"]
+            assert all(item[key] is not None for item in items)
+            total = len(sql_log)
+            if size == SMALL:
+                total_before[url] = total
+            else:
+                assert len(items) == 14  # noqa: PLR2004 - 2 + 12
+                assert total == total_before[url]
+                assert _office_selects(sql_log) == 1