diff --git a/apps/backend/src/modules/tbank/services/broker-operation-sync.service.spec.ts b/apps/backend/src/modules/tbank/services/broker-operation-sync.service.spec.ts
index ae67096..14bc828 100644
--- a/apps/backend/src/modules/tbank/services/broker-operation-sync.service.spec.ts
+++ b/apps/backend/src/modules/tbank/services/broker-operation-sync.service.spec.ts
@@ -61,11 +61,95 @@ describe('BrokerOperationSyncService', () => {
     });
 
     expect(result.upserted).toBe(1);
+    expect(operations.getOperations).toHaveBeenNthCalledWith(2, 'acc-1', {
+      from: '2026-06-01T00:00:00.000Z',
+      to: '2026-06-16T00:00:00.000Z',
+      cursor: 'next',
+      limit: 1000,
+      state: 'OPERATION_STATE_EXECUTED',
+    });
     expect(prisma.brokerOperation.upsert).toHaveBeenCalledWith(
       expect.objectContaining({
         where: { accountId_cursor: { accountId: 'acc-1', cursor: 'c1' } },
       }),
     );
-    expect(prisma.brokerOperationSyncState.upsert).toHaveBeenCalled();
+    expect(prisma.brokerOperationSyncState.upsert).toHaveBeenCalledWith(
+      expect.objectContaining({
+        update: expect.objectContaining({ lastCursor: 'next' }),
+      }),
+    );
+  });
+
+  it('stores operations under the synced account id', async () => {
+    vi.mocked(operations.getOperations).mockResolvedValueOnce({
+      data: {
+        accountId: 'acc-1',
+        hasNext: false,
+        nextCursor: null,
+        asOf: '2026-06-16T00:00:00.000Z',
+        items: [
+          {
+            cursor: 'c1',
+            accountId: 'unexpected-account',
+            id: 'op-1',
+            parentOperationId: null,
+            date: null,
+            type: 'OPERATION_TYPE_BUY',
+            category: 'trade',
+            description: null,
+            state: null,
+            instrumentUid: null,
+            figi: null,
+            ticker: null,
+            classCode: null,
+            instrumentType: null,
+            payment: null,
+            price: null,
+            commission: null,
+            yield: null,
+            accruedInt: null,
+            quantity: null,
+            quantityDone: null,
+          },
+        ],
+      },
+      meta: { fromCache: false, cachedAt: null },
+    });
+
+    const service = new BrokerOperationSyncService(operations, prisma);
+    await service.syncAccount('acc-1', {
+      from: '2026-06-01T00:00:00.000Z',
+      to: '2026-06-16T00:00:00.000Z',
+    });
+
+    expect(prisma.brokerOperation.upsert).toHaveBeenCalledWith(
+      expect.objectContaining({
+        where: { accountId_cursor: { accountId: 'acc-1', cursor: 'c1' } },
+        create: expect.objectContaining({ accountId: 'acc-1' }),
+        update: expect.objectContaining({ accountId: 'acc-1' }),
+      }),
+    );
+  });
+
+  it('fails when a page claims more data without a next cursor', async () => {
+    vi.mocked(operations.getOperations).mockResolvedValueOnce({
+      data: {
+        accountId: 'acc-1',
+        hasNext: true,
+        nextCursor: null,
+        asOf: '2026-06-16T00:00:00.000Z',
+        items: [],
+      },
+      meta: { fromCache: false, cachedAt: null },
+    });
+
+    const service = new BrokerOperationSyncService(operations, prisma);
+
+    await expect(
+      service.syncAccount('acc-1', {
+        from: '2026-06-01T00:00:00.000Z',
+        to: '2026-06-16T00:00:00.000Z',
+      }),
+    ).rejects.toThrow('T-Bank returned hasNext without nextCursor');
   });
 });
diff --git a/apps/backend/src/modules/tbank/services/broker-operation-sync.service.ts b/apps/backend/src/modules/tbank/services/broker-operation-sync.service.ts
index 4912b0f..2d54fb1 100644
--- a/apps/backend/src/modules/tbank/services/broker-operation-sync.service.ts
+++ b/apps/backend/src/modules/tbank/services/broker-operation-sync.service.ts
@@ -1,4 +1,4 @@
-import { Injectable } from '@nestjs/common';
+import { Injectable, InternalServerErrorException } from '@nestjs/common';
 import { PrismaService } from '../../prisma/prisma.service';
 import type { BrokerOperation } from '../types/broker.types';
 import { BrokerOperationsService } from './broker-operations.service';
@@ -20,6 +20,7 @@ export class BrokerOperationSyncService {
     range: BrokerOperationSyncRange,
   ): Promise<{ upserted: number }> {
     let cursor: string | undefined;
+    let lastCursor: string | null = null;
     let upserted = 0;
 
     do {
@@ -32,24 +33,35 @@ export class BrokerOperationSyncService {
       });
 
       for (const operation of page.data.items) {
-        await this.upsertOperation(operation);
+        await this.upsertOperation(accountId, operation);
         upserted++;
       }
 
-      cursor = page.data.nextCursor ?? undefined;
-      if (!page.data.hasNext) break;
+      const nextCursor = page.data.nextCursor ?? undefined;
+      if (page.data.hasNext && !nextCursor) {
+        throw new InternalServerErrorException('T-Bank returned hasNext without nextCursor');
+      }
+
+      if (nextCursor) {
+        lastCursor = nextCursor;
+      }
+
+      cursor = nextCursor;
+      if (!page.data.hasNext) {
+        break;
+      }
     } while (cursor);
 
     await this.prisma.brokerOperationSyncState.upsert({
       where: { accountId },
       create: {
         accountId,
-        lastCursor: cursor ?? null,
+        lastCursor,
         lastSyncedFrom: new Date(range.from),
         lastSyncedTo: new Date(range.to),
       },
       update: {
-        lastCursor: cursor ?? null,
+        lastCursor,
         lastSyncedFrom: new Date(range.from),
         lastSyncedTo: new Date(range.to),
         syncedAt: new Date(),
@@ -59,11 +71,11 @@ export class BrokerOperationSyncService {
     return { upserted };
   }
 
-  private async upsertOperation(operation: BrokerOperation): Promise<void> {
+  private async upsertOperation(accountId: string, operation: BrokerOperation): Promise<void> {
     const cursor =
       operation.cursor || `${operation.id || 'operation'}:${operation.date || 'no-date'}`;
     const data = {
-      accountId: operation.accountId,
+      accountId,
       cursor,
       operationId: operation.id,
       parentOperationId: operation.parentOperationId,
@@ -86,7 +98,7 @@ export class BrokerOperationSyncService {
     };
 
     await this.prisma.brokerOperation.upsert({
-      where: { accountId_cursor: { accountId: operation.accountId, cursor } },
+      where: { accountId_cursor: { accountId, cursor } },
       create: data,
       update: data,
     });