diff --git a/src/main/java/de/financer/ResponseReason.java b/src/main/java/de/financer/ResponseReason.java
index 8e87790..bd1b02e 100644
--- a/src/main/java/de/financer/ResponseReason.java
+++ b/src/main/java/de/financer/ResponseReason.java
@@ -28,7 +28,8 @@ public enum ResponseReason {
     MISSING_TRANSACTION_ID(HttpStatus.INTERNAL_SERVER_ERROR),
     INVALID_TRANSACTION_ID(HttpStatus.INTERNAL_SERVER_ERROR),
     TRANSACTION_NOT_FOUND(HttpStatus.INTERNAL_SERVER_ERROR),
-    ACCOUNT_NOT_FOUND(HttpStatus.INTERNAL_SERVER_ERROR);
+    ACCOUNT_NOT_FOUND(HttpStatus.INTERNAL_SERVER_ERROR),
+    DUPLICATE_ACCOUNT_KEY(HttpStatus.INTERNAL_SERVER_ERROR);
 
     private HttpStatus httpStatus;
 
diff --git a/src/main/java/de/financer/service/AccountService.java b/src/main/java/de/financer/service/AccountService.java
index bcea422..67deea5 100644
--- a/src/main/java/de/financer/service/AccountService.java
+++ b/src/main/java/de/financer/service/AccountService.java
@@ -9,6 +9,7 @@ import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Propagation;
 import org.springframework.transaction.annotation.Transactional;
@@ -61,7 +62,7 @@ public class AccountService {
      *         {@link ResponseReason#UNKNOWN_ERROR} if an unexpected error occurs and
      *         {@link ResponseReason#OK} if the operation completed successfully. Never returns <code>null</code>.
      */
-    @Transactional(propagation = Propagation.REQUIRED)
+    @Transactional(propagation = Propagation.SUPPORTS)
     public ResponseReason createAccount(String key, String type) {
         if (!AccountType.isValidType(type)) {
             return ResponseReason.INVALID_ACCOUNT_TYPE;
@@ -79,6 +80,11 @@ public class AccountService {
         try {
             this.accountRepository.save(account);
         }
+        catch (DataIntegrityViolationException dive) {
+            LOGGER.error(String.format("Duplicate key! %s|%s", key, type), dive);
+
+            return ResponseReason.DUPLICATE_ACCOUNT_KEY;
+        }
         catch (Exception e) {
             LOGGER.error(String.format("Could not save account %s|%s", key, type), e);