diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4f13393d1a..668441686c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -42,6 +42,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed the missing localization of the date picker in the asset profile details dialog of the admin control panel
 - Fixed the missing tooltip of the client of the last request in the users table of the admin control panel
 
+### Fixed
+
+- Fixed an issue in the activities import where global asset profiles were duplicated as custom asset profiles
+
 ## 3.88.0 - 2026-10-17
 
 ### Added
diff --git a/apps/api/src/app/import/import.service.spec.ts b/apps/api/src/app/import/import.service.spec.ts
index d6d41134a5..fdf225820a 100644
--- a/apps/api/src/app/import/import.service.spec.ts
+++ b/apps/api/src/app/import/import.service.spec.ts
@@ -33,6 +33,7 @@ describe('ImportService', () => {
   let addSymbolProfile: jest.Mock;
   let createActivity: jest.Mock;
   let gatherSymbols: jest.Mock;
+  let getSymbolProfiles: jest.Mock;
   let importService: ImportService;
   let updateManyMarketData: jest.Mock;
 
@@ -46,6 +47,7 @@ describe('ImportService', () => {
     addSymbolProfile = jest.fn();
     createActivity = jest.fn();
     gatherSymbols = jest.fn();
+    getSymbolProfiles = jest.fn().mockResolvedValue([]);
     updateManyMarketData = jest.fn();
 
     const validateActivities = jest.fn(
@@ -94,8 +96,8 @@ describe('ImportService', () => {
       null,
       {
         add: addSymbolProfile,
-        getCustomSymbolProfilesByNames: jest.fn().mockResolvedValue([]),
-        getSymbolProfiles: jest.fn().mockResolvedValue([])
+        getSymbolProfiles,
+        getCustomSymbolProfilesByNames: jest.fn().mockResolvedValue([])
       } as unknown as SymbolProfileService,
       {
         getTagsForUser: jest.fn().mockResolvedValue([])
@@ -481,6 +483,82 @@ describe('ImportService', () => {
       ]);
     });
 
+    it('reuses a global asset profile without updating its market data', async () => {
+      getSymbolProfiles.mockResolvedValue([
+        { dataSource: DataSource.YAHOO, symbol: 'AAPL', userId: null }
+      ]);
+
+      mockCreatedAssetProfiles([
+        { dataSource: DataSource.YAHOO, symbol: 'AAPL' }
+      ]);
+
+      await importActivities({
+        activitiesDto: [
+          createActivityDto({
+            dataSource: DataSource.YAHOO,
+            date: '2024-01-01T00:00:00.000Z',
+            symbol: 'AAPL',
+            type: 'BUY'
+          })
+        ],
+        assetProfilesWithMarketDataDto: [
+          {
+            currency: 'USD',
+            dataSource: DataSource.YAHOO,
+            marketData: [{ date: '2024-01-01', marketPrice: 1 }],
+            name: 'Apple Inc.',
+            symbol: 'AAPL'
+          }
+        ]
+      });
+
+      expect(addSymbolProfile).not.toHaveBeenCalled();
+      expect(updateManyMarketData).not.toHaveBeenCalled();
+
+      expect(
+        createActivity.mock.calls[0][0].SymbolProfile.connectOrCreate.create
+      ).toMatchObject({ dataSource: DataSource.YAHOO, symbol: 'AAPL' });
+    });
+
+    it('creates a custom asset profile with a UUID instead of the asset profile of another user', async () => {
+      getSymbolProfiles.mockResolvedValue([
+        {
+          dataSource: DataSource.MANUAL,
+          symbol: CUSTOM_ASSET_PROFILE_SYMBOL,
+          userId: 'other-user-id'
+        }
+      ]);
+
+      mockCreatedAssetProfiles([
+        { dataSource: DataSource.MANUAL, symbol: CUSTOM_ASSET_PROFILE_SYMBOL }
+      ]);
+
+      await importActivities({
+        activitiesDto: [
+          createActivityDto({
+            dataSource: DataSource.MANUAL,
+            date: '2024-01-01T00:00:00.000Z',
+            symbol: CUSTOM_ASSET_PROFILE_SYMBOL,
+            type: 'BUY'
+          })
+        ],
+        assetProfilesWithMarketDataDto: [
+          {
+            currency: 'USD',
+            dataSource: DataSource.MANUAL,
+            marketData: [{ date: '2024-01-01', marketPrice: 100 }],
+            name: 'Gold',
+            symbol: CUSTOM_ASSET_PROFILE_SYMBOL
+          }
+        ]
+      });
+
+      const { symbol } = addSymbolProfile.mock.calls[0][0];
+
+      expect(isUUID(symbol)).toBe(true);
+      expect(symbol).not.toBe(CUSTOM_ASSET_PROFILE_SYMBOL);
+    });
+
     it('keeps the asset profiles of the activities in a dry run', async () => {
       const activities = await importActivities({
         activitiesDto: [
diff --git a/apps/api/src/app/import/import.service.ts b/apps/api/src/app/import/import.service.ts
index 2d09cb78df..dac423d682 100644
--- a/apps/api/src/app/import/import.service.ts
+++ b/apps/api/src/app/import/import.service.ts
@@ -624,10 +624,12 @@ export class ImportService {
           }
         );
 
+        const isGlobalAssetProfile = existingAssetProfile?.userId === null;
+
         // If there is no asset profile or if the asset profile belongs to a
         // different user, then reuse the custom asset profile of the user or
         // create a new asset profile
-        if (existingAssetProfile?.userId !== user.id) {
+        if (!isGlobalAssetProfile && existingAssetProfile?.userId !== user.id) {
           // Check if the user has a custom asset profile with the same name.
           // Skip asset profiles with a legacy free-text symbol as they would
           // fail the symbol validation on a future import.
@@ -689,7 +691,8 @@ export class ImportService {
           }
         }
 
-        if (!isDryRun) {
+        // Never let an import change the market data of a global asset profile
+        if (!isDryRun && !isGlobalAssetProfile) {
           const marketDataObjects = (
             assetProfileWithMarketData.marketData ?? []
           ).map((marketData) => {