diff --git a/CHANGELOG.md b/CHANGELOG.md
index 28d3b6ea0..8c66c9c07 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Deprecated `firstBuyDate` in favor of `dateOfFirstActivity` in the endpoint `GET api/v1/portfolio/holding/:dataSource/:symbol`
 - Upgraded `countries-list` from version `3.2.0` to `3.2.2`
 
 ## 2.231.0 - 2026-01-17
diff --git a/apps/api/src/app/import/import.service.ts b/apps/api/src/app/import/import.service.ts
index 3f8bd2cde..7e8e333b9 100644
--- a/apps/api/src/app/import/import.service.ts
+++ b/apps/api/src/app/import/import.service.ts
@@ -82,7 +82,7 @@ export class ImportService {
         filterBySymbol: symbol
       });
 
-      const { firstBuyDate, historicalData } = holding;
+      const { dateOfFirstActivity, historicalData } = holding;
 
       const [{ accounts }, { activities }, [assetProfile], dividends] =
         await Promise.all([
@@ -95,7 +95,7 @@ export class ImportService {
             filters,
             userCurrency,
             userId,
-            startDate: parseDate(firstBuyDate)
+            startDate: parseDate(dateOfFirstActivity)
           }),
           this.symbolProfileService.getSymbolProfiles([
             {
@@ -106,7 +106,7 @@ export class ImportService {
           await this.dataProviderService.getDividends({
             dataSource,
             symbol,
-            from: parseDate(firstBuyDate),
+            from: parseDate(dateOfFirstActivity),
             granularity: 'day',
             to: new Date()
           })
diff --git a/apps/api/src/app/portfolio/portfolio.service.ts b/apps/api/src/app/portfolio/portfolio.service.ts
index 5fc2224eb..9a6f6af62 100644
--- a/apps/api/src/app/portfolio/portfolio.service.ts
+++ b/apps/api/src/app/portfolio/portfolio.service.ts
@@ -923,6 +923,7 @@ export class PortfolioService {
       activitiesCount: transactionCount,
       averagePrice: averagePrice.toNumber(),
       dataProviderInfo: portfolioCalculator.getDataProviderInfos()?.[0],
+      dateOfFirstActivity: firstBuyDate,
       dividendInBaseCurrency: dividendInBaseCurrency.toNumber(),
       dividendYieldPercent: dividendYieldPercent.toNumber(),
       dividendYieldPercentWithCurrencyEffect:
diff --git a/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.component.ts b/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.component.ts
index 95c58d35a..427386796 100644
--- a/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.component.ts
+++ b/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.component.ts
@@ -116,11 +116,11 @@ export class GfHoldingDetailDialogComponent implements OnDestroy, OnInit {
   };
   public dataProviderInfo: DataProviderInfo;
   public dataSource: MatTableDataSource<Activity>;
+  public dateOfFirstActivity: string;
   public dividendInBaseCurrency: number;
   public dividendInBaseCurrencyPrecision = 2;
   public dividendYieldPercentWithCurrencyEffect: number;
   public feeInBaseCurrency: number;
-  public firstBuyDate: string;
   public hasPermissionToCreateOwnTag: boolean;
   public hasPermissionToReadMarketDataOfOwnAssetProfile: boolean;
   public historicalDataItems: LineChartItem[];
@@ -267,10 +267,10 @@ export class GfHoldingDetailDialogComponent implements OnDestroy, OnInit {
           activitiesCount,
           averagePrice,
           dataProviderInfo,
+          dateOfFirstActivity,
           dividendInBaseCurrency,
           dividendYieldPercentWithCurrencyEffect,
           feeInBaseCurrency,
-          firstBuyDate,
           historicalData,
           investmentInBaseCurrencyWithCurrencyEffect,
           marketPrice,
@@ -298,6 +298,7 @@ export class GfHoldingDetailDialogComponent implements OnDestroy, OnInit {
           this.benchmarkDataItems = [];
           this.countries = {};
           this.dataProviderInfo = dataProviderInfo;
+          this.dateOfFirstActivity = dateOfFirstActivity;
           this.dividendInBaseCurrency = dividendInBaseCurrency;
 
           if (
@@ -312,7 +313,6 @@ export class GfHoldingDetailDialogComponent implements OnDestroy, OnInit {
             dividendYieldPercentWithCurrencyEffect;
 
           this.feeInBaseCurrency = feeInBaseCurrency;
-          this.firstBuyDate = firstBuyDate;
 
           this.hasPermissionToReadMarketDataOfOwnAssetProfile =
             hasPermission(
@@ -461,16 +461,16 @@ export class GfHoldingDetailDialogComponent implements OnDestroy, OnInit {
             }
           }
 
-          if (isToday(parseISO(this.firstBuyDate))) {
+          if (isToday(parseISO(this.dateOfFirstActivity))) {
             // Add average price
             this.historicalDataItems.push({
-              date: this.firstBuyDate,
+              date: this.dateOfFirstActivity,
               value: this.averagePrice
             });
 
             // Add benchmark 1
             this.benchmarkDataItems.push({
-              date: this.firstBuyDate,
+              date: this.dateOfFirstActivity,
               value: averagePrice
             });
 
@@ -501,7 +501,7 @@ export class GfHoldingDetailDialogComponent implements OnDestroy, OnInit {
 
           if (
             this.benchmarkDataItems[0]?.value === undefined &&
-            isSameMonth(parseISO(this.firstBuyDate), new Date())
+            isSameMonth(parseISO(this.dateOfFirstActivity), new Date())
           ) {
             this.benchmarkDataItems[0].value = this.averagePrice;
           }
diff --git a/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.html b/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.html
index f52286160..f9329dbfb 100644
--- a/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.html
+++ b/apps/client/src/app/components/holding-detail-dialog/holding-detail-dialog.html
@@ -215,7 +215,7 @@
                 [deviceType]="data.deviceType"
                 [isDate]="true"
                 [locale]="data.locale"
-                [value]="firstBuyDate"
+                [value]="dateOfFirstActivity"
                 >First Activity</gf-value
               >
             </div>
@@ -400,7 +400,7 @@
           <gf-historical-market-data-editor
             [currency]="SymbolProfile?.currency"
             [dataSource]="SymbolProfile?.dataSource"
-            [dateOfFirstActivity]="firstBuyDate"
+            [dateOfFirstActivity]="dateOfFirstActivity"
             [locale]="data.locale"
             [marketData]="marketDataItems"
             [symbol]="SymbolProfile?.symbol"
diff --git a/libs/common/src/lib/interfaces/responses/portfolio-holding-response.interface.ts b/libs/common/src/lib/interfaces/responses/portfolio-holding-response.interface.ts
index 95c1c3689..1d1ac1b11 100644
--- a/libs/common/src/lib/interfaces/responses/portfolio-holding-response.interface.ts
+++ b/libs/common/src/lib/interfaces/responses/portfolio-holding-response.interface.ts
@@ -11,11 +11,15 @@ export interface PortfolioHoldingResponse {
   activitiesCount: number;
   averagePrice: number;
   dataProviderInfo: DataProviderInfo;
+  dateOfFirstActivity: string;
   dividendInBaseCurrency: number;
   dividendYieldPercent: number;
   dividendYieldPercentWithCurrencyEffect: number;
   feeInBaseCurrency: number;
+
+  /** @deprecated use dateOfFirstActivity */
   firstBuyDate: string;
+
   grossPerformance: number;
   grossPerformancePercent: number;
   grossPerformancePercentWithCurrencyEffect: number;