diff --git a/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/securitiesaccount/Holding.kt b/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/securitiesaccount/Holding.kt
index 1dcb84a4..469439f2 100644
--- a/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/securitiesaccount/Holding.kt
+++ b/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/securitiesaccount/Holding.kt
@@ -45,5 +45,7 @@ open class Holding(
 
     val buyingDate: LocalDate? = null,
 ) {
+    val identifier: String by lazy { "${isin}_$wkn" }
+
     override fun toString() = "$name $totalBalance $currency"
 }
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