diff --git a/packages/http-routes/src/routes/web/merge.test.ts b/packages/http-routes/src/routes/web/merge.test.ts
index d79c54d5..db1699b3 100644
--- a/packages/http-routes/src/routes/web/merge.test.ts
+++ b/packages/http-routes/src/routes/web/merge.test.ts
@@ -82,6 +82,58 @@ test('forwards the session gap threshold when importing merged output', async (t
   assert.deepEqual(receivedOptions, { sessionGapThreshold: 7200 })
 })
 
+test('preserves the owner id when exporting existing private sessions for merge', async (t) => {
+  const rootDir = makeTempDir()
+  t.after(() => fs.rmSync(rootDir, { recursive: true, force: true }))
+
+  const pathProvider = createPathProvider(rootDir)
+  const dbManager = new DatabaseManager(pathProvider, { nativeBinding, allowMissingRuntimeForTests: true })
+  const mergeSessionCache = new MergeSessionCache(pathProvider, { nativeBinding })
+  const db = dbManager.openRawSessionDatabase('private-session', {
+    create: true,
+    initializeChatTables: true,
+  })
+  db.prepare('INSERT INTO meta (name, platform, type, imported_at, owner_id) VALUES (?, ?, ?, ?, ?)').run(
+    'Private chat',
+    'qq',
+    'private',
+    1_700_000_000,
+    'owner'
+  )
+  const owner = db.prepare('INSERT INTO member (platform_id, account_name) VALUES (?, ?)').run('owner', 'Owner')
+  db.prepare('INSERT INTO member (platform_id, account_name) VALUES (?, ?)').run('peer', 'Peer')
+  db.prepare('INSERT INTO message (sender_id, sender_account_name, ts, type, content) VALUES (?, ?, ?, ?, ?)').run(
+    owner.lastInsertRowid,
+    'Owner',
+    1_700_000_001,
+    0,
+    'hello'
+  )
+  db.close()
+
+  const app = Fastify()
+  registerMergeRoutes(app, { dbManager, mergeSessionCache })
+  await app.ready()
+  t.after(() => app.close())
+
+  const exportResponse = await app.inject({
+    method: 'POST',
+    url: '/_web/sessions/export-for-merge',
+    payload: { sessionIds: ['private-session'] },
+  })
+  assert.equal(exportResponse.statusCode, 200)
+  const handles = exportResponse.json().handles as Array<{ handle: string }>
+
+  const mergeResponse = await app.inject({
+    method: 'POST',
+    url: '/_web/merge/execute',
+    payload: { handles: handles.map(({ handle }) => handle), outputName: 'Merged private chat' },
+  })
+
+  assert.equal(mergeResponse.statusCode, 200)
+  assert.equal(mergeResponse.json().data.meta.ownerId, 'owner')
+})
+
 test('keeps every distinct platform message when merging a source with its superset', async (t) => {
   const rootDir = makeTempDir()
   t.after(() => fs.rmSync(rootDir, { recursive: true, force: true }))
diff --git a/packages/http-routes/src/routes/web/merge.ts b/packages/http-routes/src/routes/web/merge.ts
index 47399620..7d669f8a 100644
--- a/packages/http-routes/src/routes/web/merge.ts
+++ b/packages/http-routes/src/routes/web/merge.ts
@@ -240,6 +240,7 @@ export function registerMergeRoutes(server: FastifyInstance, ctx: MergeRoutesCon
         type: exported.meta.type,
         groupId: exported.meta.groupId,
         groupAvatar: exported.meta.groupAvatar,
+        ownerId: exported.meta.ownerId,
       })
       writer.writeMembers(
         exported.members.map((m) => ({
diff --git a/packages/node-runtime/src/merger/__tests__/merger.test.ts b/packages/node-runtime/src/merger/__tests__/merger.test.ts
index 7dd7e683..4dd0e9e2 100644
--- a/packages/node-runtime/src/merger/__tests__/merger.test.ts
+++ b/packages/node-runtime/src/merger/__tests__/merger.test.ts
@@ -133,6 +133,61 @@ describe('buildMergedOutput', () => {
     assert.equal(result.chatLabData.meta.platform, 'mixed')
   })
 
+  it('preserves the only non-empty owner id and drops conflicting owner ids', () => {
+    const messages = [{ senderPlatformId: 'peer', timestamp: 100, type: 0, content: 'hello' }]
+    const members = [{ platformId: 'owner' }, { platformId: 'peer' }]
+    const sourceWithoutOwner = createMockSource({ name: 'Private', platform: 'qq', type: 'private' }, members, messages)
+    const sourceWithOwner = createMockSource(
+      { name: 'Private', platform: 'qq', type: 'private', ownerId: 'owner' } as MergerSourceMeta & {
+        ownerId: string
+      },
+      members,
+      messages
+    )
+
+    const retained = buildMergedOutput(
+      [
+        { source: sourceWithoutOwner, filename: 'without-owner.json' },
+        { source: sourceWithOwner, filename: 'with-owner.json' },
+      ],
+      'Merged'
+    )
+    assert.equal((retained.chatLabData.meta as { ownerId?: string }).ownerId, 'owner')
+
+    const invalid = buildMergedOutput(
+      [
+        {
+          source: createMockSource(
+            { name: 'Private', platform: 'qq', type: 'private', ownerId: 'missing-owner' },
+            members,
+            messages
+          ),
+          filename: 'invalid-owner.json',
+        },
+      ],
+      'Merged'
+    )
+    assert.equal((invalid.chatLabData.meta as { ownerId?: string }).ownerId, undefined)
+
+    const conflicting = buildMergedOutput(
+      [
+        { source: sourceWithOwner, filename: 'first.json' },
+        {
+          source: createMockSource(
+            { name: 'Private', platform: 'qq', type: 'private', ownerId: 'different-owner' } as MergerSourceMeta & {
+              ownerId: string
+            },
+            members,
+            messages
+          ),
+          filename: 'second.json',
+        },
+      ],
+      'Merged'
+    )
+    assert.equal((conflicting.chatLabData.meta as { ownerId?: string }).ownerId, undefined)
+  })
+
   it('keeps same-platform message IDs separate across unrelated private chats', () => {
     const first = createMockSource(
       { name: 'Alice', platform: 'telegram', type: 'private' },
@@ -425,7 +480,8 @@ describe('exportSessionToJson', () => {
         platform TEXT NOT NULL,
         type TEXT NOT NULL,
         group_id TEXT,
-        group_avatar TEXT
+        group_avatar TEXT,
+        owner_id TEXT
       );
       CREATE TABLE member (
         id INTEGER PRIMARY KEY,
@@ -445,7 +501,7 @@ describe('exportSessionToJson', () => {
         platform_message_id TEXT,
         reply_to_message_id TEXT
       );
-      INSERT INTO meta (name, platform, type) VALUES ('Test', 'qq', 'group');
+      INSERT INTO meta (name, platform, type, owner_id) VALUES ('Test', 'qq', 'private', 'owner');
       INSERT INTO member (id, platform_id, account_name) VALUES (1, 'alice', 'Alice');
       INSERT INTO message (
         sender_id, sender_account_name, ts, type, content, platform_message_id, reply_to_message_id
@@ -455,6 +511,7 @@ describe('exportSessionToJson', () => {
     try {
       const exported = exportSessionToJson(new BetterSqliteAdapter(rawDb))
       assert.equal(exported.chatlab.version, CHATLAB_FORMAT_VERSION)
+      assert.equal((exported.meta as { ownerId?: string }).ownerId, 'owner')
       assert.equal(exported.messages[0].platformMessageId, 'message-1')
       assert.equal(exported.messages[0].replyToMessageId, 'message-0')
     } finally {
diff --git a/packages/node-runtime/src/merger/index.ts b/packages/node-runtime/src/merger/index.ts
index 29e7cbbb..490463a6 100644
--- a/packages/node-runtime/src/merger/index.ts
+++ b/packages/node-runtime/src/merger/index.ts
@@ -42,6 +42,7 @@ export interface MergerSourceMeta {
   type: string
   groupId?: string
   groupAvatar?: string
+  ownerId?: string
 }
 
 function createMessageScope(meta: MergerSourceMeta | null, members: MergerMember[], sourceIndex: number): string {
@@ -188,6 +189,7 @@ export interface ChatLabMeta {
   sources: MergeSourceInfo[]
   groupId?: string
   groupAvatar?: string
+  ownerId?: string
 }
 
 export interface ChatLabOutput {
@@ -391,6 +393,9 @@ export function buildMergedOutput(
   const groupAvatar = groupId
     ? metas.filter(({ meta }) => meta?.groupId === groupId).pop()?.meta?.groupAvatar
     : undefined
+  const ownerIds = new Set(metas.map(({ meta }) => meta?.ownerId).filter((id): id is string => Boolean(id)))
+  const ownerCandidate = uniquePlatforms.length === 1 && ownerIds.size === 1 ? [...ownerIds][0] : undefined
+  const ownerId = ownerCandidate && memberMap.has(ownerCandidate) ? ownerCandidate : undefined
 
   const chatLabData: ChatLabOutput = {
     chatlab: {
@@ -406,6 +411,7 @@ export function buildMergedOutput(
       sources,
       groupId,
       groupAvatar,
+      ownerId,
     },
     members: Array.from(memberMap.values()),
     messages: mergedMessages,
diff --git a/packages/node-runtime/src/merger/temp-db.ts b/packages/node-runtime/src/merger/temp-db.ts
index fb817e2e..02c2c324 100644
--- a/packages/node-runtime/src/merger/temp-db.ts
+++ b/packages/node-runtime/src/merger/temp-db.ts
@@ -142,6 +142,7 @@ export interface TempDbMeta {
   type: string
   groupId?: string
   groupAvatar?: string
+  ownerId?: string
 }
 
 export class TempDbReader {
@@ -153,7 +154,14 @@ export class TempDbReader {
 
   getMeta(): TempDbMeta | null {
     const row = this.db.prepare('SELECT * FROM meta LIMIT 1').get() as
-      | { name: string; platform: string; type: string; group_id: string | null; group_avatar: string | null }
+      | {
+          name: string
+          platform: string
+          type: string
+          group_id: string | null
+          group_avatar: string | null
+          owner_id: string | null
+        }
       | undefined
     if (!row) return null
     return {
@@ -162,6 +170,7 @@ export class TempDbReader {
       type: row.type,
       groupId: row.group_id || undefined,
       groupAvatar: row.group_avatar || undefined,
+      ownerId: row.owner_id || undefined,
     }
   }
 
@@ -274,6 +283,7 @@ function createDataSourceFromReader(reader: TempDbReader): MergerDataSource {
         type: meta.type,
         groupId: meta.groupId,
         groupAvatar: meta.groupAvatar,
+        ownerId: meta.ownerId,
       }
     },
     getMembers(): MergerMember[] {
@@ -310,7 +320,14 @@ function createDataSourceFromReader(reader: TempDbReader): MergerDataSource {
 
 export interface ExportedSession {
   chatlab: { version: typeof CHATLAB_FORMAT_VERSION; exportedAt: number; generator: string; description: string }
-  meta: { name: string; platform: string; type: string; groupId?: string; groupAvatar?: string }
+  meta: {
+    name: string
+    platform: string
+    type: string
+    groupId?: string
+    groupAvatar?: string
+    ownerId?: string
+  }
   members: Array<{ platformId: string; accountName: string; groupNickname?: string; avatar?: string }>
   messages: Array<{
     platformMessageId?: string
@@ -330,7 +347,14 @@ export interface ExportedSession {
  */
 export function exportSessionToJson(db: DatabaseAdapter): ExportedSession {
   const meta = db.prepare('SELECT * FROM meta').get() as
-    | { name: string; platform: string; type: string; group_id?: string; group_avatar?: string }
+    | {
+        name: string
+        platform: string
+        type: string
+        group_id?: string
+        group_avatar?: string
+        owner_id?: string
+      }
     | undefined
 
   if (!meta) throw new Error('Cannot read session meta')
@@ -373,6 +397,7 @@ export function exportSessionToJson(db: DatabaseAdapter): ExportedSession {
       type: meta.type,
       groupId: meta.group_id,
       groupAvatar: meta.group_avatar,
+      ownerId: meta.owner_id,
     },
     members: members.map((m) => ({
       platformId: m.platform_id,