diff --git a/fints4javaLib/src/main/kotlin/net/dankito/fints/banks/LuceneBankFinder.kt b/fints4javaLib/src/main/kotlin/net/dankito/fints/banks/LuceneBankFinder.kt
index bbbfca59..99f55a47 100644
--- a/fints4javaLib/src/main/kotlin/net/dankito/fints/banks/LuceneBankFinder.kt
+++ b/fints4javaLib/src/main/kotlin/net/dankito/fints/banks/LuceneBankFinder.kt
@@ -141,6 +141,8 @@ open class LuceneBankFinder(indexFolder: File) : BankFinderBase(), IBankFinder {
             writer.updateDocument(IndexedBankListFileHashIdFieldName, IndexedBankListFileHashIdFieldValue,
                 fields.storedField(IndexedBankListFileHashFieldName, bankListFileHash)
             )
+
+            writer.optimizeIndex()
         }
     }