diff --git a/apps/api/src/app/activities/activities.service.ts b/apps/api/src/app/activities/activities.service.ts
index 53741a3199..19578f19b2 100644
--- a/apps/api/src/app/activities/activities.service.ts
+++ b/apps/api/src/app/activities/activities.service.ts
@@ -23,6 +23,7 @@ import {
 import {
   canDeleteAssetProfile,
   getAssetProfileIdentifier,
+  isGhostfolioSymbol,
   isValidManualSymbol
 } from '@ghostfolio/common/helper';
 import {
@@ -205,6 +206,21 @@ export class ActivitiesService {
       ) {
         // Connect custom asset profile (clone)
         symbol = data.SymbolProfile.connectOrCreate.create.symbol;
+
+        if (isGhostfolioSymbol(symbol)) {
+          // Asset profiles with the Ghostfolio prefix are created in the admin
+          // control only, so they must exist already
+          const existingAssetProfile =
+            await this.prismaService.symbolProfile.findUnique({
+              where: { dataSource_symbol: { dataSource, symbol } }
+            });
+
+          if (!existingAssetProfile) {
+            throw new Error(
+              `Asset profile not found for ${symbol} (${dataSource})`
+            );
+          }
+        }
       } else {
         // Create custom asset profile
         name = name ?? data.SymbolProfile.connectOrCreate.create.symbol;
diff --git a/apps/api/src/app/import/import.service.ts b/apps/api/src/app/import/import.service.ts
index ac47cdb5cd..4f22cfa23c 100644
--- a/apps/api/src/app/import/import.service.ts
+++ b/apps/api/src/app/import/import.service.ts
@@ -11,11 +11,13 @@ import { SymbolProfileService } from '@ghostfolio/api/services/symbol-profile/sy
 import { TagService } from '@ghostfolio/api/services/tag/tag.service';
 import {
   ACTIVITY_TYPES_WITH_GENERATED_UUID_SYMBOL,
-  DATA_GATHERING_QUEUE_PRIORITY_HIGH
+  DATA_GATHERING_QUEUE_PRIORITY_HIGH,
+  ghostfolioPrefix
 } from '@ghostfolio/common/config';
 import { CreateAssetProfileDto, CreateOrderDto } from '@ghostfolio/common/dtos';
 import {
   getAssetProfileIdentifier,
+  isGhostfolioSymbol,
   parseDate
 } from '@ghostfolio/common/helper';
 import {
@@ -34,7 +36,7 @@ import { Injectable } from '@nestjs/common';
 import { DataSource, Prisma } from '@prisma/client';
 import { Big } from 'big.js';
 import { endOfToday, isAfter, isSameSecond, parseISO } from 'date-fns';
-import { omit, uniqBy } from 'lodash';
+import { omit, uniq, uniqBy } from 'lodash';
 import { randomUUID } from 'node:crypto';
 
 import { ImportDataDto } from './import-data.dto';
@@ -193,6 +195,11 @@ export class ImportService {
     const tagIdMapping: { [oldTagId: string]: string } = {};
     const userCurrency = user.settings.settings.baseCurrency;
 
+    await this.validateGhostfolioSymbols({
+      activitiesDto,
+      assetProfilesWithMarketDataDto
+    });
+
     const existingTagsOfUser =
       tagsDto?.length || (!isDryRun && accountsWithBalancesDto?.length)
         ? await this.tagService.getTagsForUser(user.id)
@@ -749,4 +756,45 @@ export class ImportService {
 
     return uniqueAccountIds.size === 1;
   }
+
+  private async validateGhostfolioSymbols({
+    activitiesDto,
+    assetProfilesWithMarketDataDto
+  }: {
+    activitiesDto: ImportDataDto['activities'];
+    assetProfilesWithMarketDataDto: ImportDataDto['assetProfiles'];
+  }) {
+    const symbols = uniq(
+      [...(activitiesDto ?? []), ...(assetProfilesWithMarketDataDto ?? [])].map(
+        ({ symbol }) => {
+          return symbol;
+        }
+      )
+    ).filter((symbol) => {
+      return isGhostfolioSymbol(symbol);
+    });
+
+    if (symbols.length === 0) {
+      return;
+    }
+
+    const existingAssetProfiles =
+      await this.symbolProfileService.getSymbolProfiles(
+        symbols.map((symbol) => {
+          return { symbol, dataSource: DataSource.MANUAL };
+        })
+      );
+
+    const missingSymbols = symbols.filter((symbol) => {
+      return !existingAssetProfiles.some(({ symbol: existingSymbol }) => {
+        return existingSymbol === symbol;
+      });
+    });
+
+    if (missingSymbols.length > 0) {
+      throw new Error(
+        `Asset profiles with the prefix "${ghostfolioPrefix}_" can only be created in the admin control (${missingSymbols.join(', ')})`
+      );
+    }
+  }
 }
diff --git a/libs/common/src/lib/helper.spec.ts b/libs/common/src/lib/helper.spec.ts
index 0fbea13e93..bf7269bcc6 100644
--- a/libs/common/src/lib/helper.spec.ts
+++ b/libs/common/src/lib/helper.spec.ts
@@ -3,6 +3,7 @@ import {
   getNumberFormatGroup,
   isCurrency,
   isCurrencySymbol,
+  isGhostfolioSymbol,
   isValidManualSymbol
 } from '@ghostfolio/common/helper';
 
@@ -197,6 +198,22 @@ describe('Helper', () => {
     });
   });
 
+  describe('Is Ghostfolio symbol', () => {
+    it('Ghostfolio-prefixed symbol', () => {
+      expect(isGhostfolioSymbol('GF_PENTHOUSE_APARTMENT')).toEqual(true);
+    });
+
+    it('UUID', () => {
+      expect(
+        isGhostfolioSymbol('7e91b7d4-1430-4212-8380-289a06c9bbc1')
+      ).toEqual(false);
+    });
+
+    it('Human-readable symbol', () => {
+      expect(isGhostfolioSymbol('PENTHOUSE_APARTMENT')).toEqual(false);
+    });
+  });
+
   describe('Is valid manual symbol', () => {
     it('UUID', () => {
       expect(
diff --git a/libs/common/src/lib/helper.ts b/libs/common/src/lib/helper.ts
index 7cf26d4b9c..2073607d4c 100644
--- a/libs/common/src/lib/helper.ts
+++ b/libs/common/src/lib/helper.ts
@@ -500,6 +500,14 @@ export function isDerivedCurrency(aCurrency: string) {
   });
 }
 
+export function isGhostfolioSymbol(aSymbol?: string) {
+  if (!aSymbol) {
+    return false;
+  }
+
+  return aSymbol.startsWith(`${ghostfolioPrefix}_`);
+}
+
 export function isRootCurrency(aCurrency: string) {
   if (aCurrency === 'USD') {
     return true;
@@ -515,7 +523,7 @@ export function isValidManualSymbol(aSymbol?: string) {
     return false;
   }
 
-  return isUUID(aSymbol) || aSymbol.startsWith(`${ghostfolioPrefix}_`);
+  return isGhostfolioSymbol(aSymbol) || isUUID(aSymbol);
 }
 
 export function parseDate(date: string): Date | undefined {