diff --git a/CHANGELOG.md b/CHANGELOG.md
index e79ed5f4f..328d7749e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Improved the error message of the currency code validation
 - Tightened the currency code validation by requiring uppercase letters
 
+### Fixed
+
+- Improved the file selector of the activities import functionality to accept case-insensitive file extensions (`.CSV` and `.JSON`)
+
 ## 2.155.0 - 2025-04-23
 
 ### Added
diff --git a/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts b/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts
index 82e78a180..20f135801 100644
--- a/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts
+++ b/apps/client/src/app/pages/portfolio/activities/import-activities-dialog/import-activities-dialog.component.ts
@@ -247,9 +247,10 @@ export class ImportActivitiesDialog implements OnDestroy {
 
     reader.onload = async (readerEvent) => {
       const fileContent = readerEvent.target.result as string;
+      const fileExtension = file.name.split('.').pop()?.toLowerCase();
 
       try {
-        if (file.name.endsWith('.json')) {
+        if (fileExtension === 'json') {
           const content = JSON.parse(fileContent);
 
           this.accounts = content.accounts;
@@ -294,7 +295,7 @@ export class ImportActivitiesDialog implements OnDestroy {
           }
 
           return;
-        } else if (file.name.endsWith('.csv')) {
+        } else if (fileExtension === 'csv') {
           const content = fileContent.split('\n').slice(1);
 
           try {