diff --git a/Layout/default/Address/Form.php b/Layout/default/Address/Form.php
index 55224e494..e29c5644c 100644
--- a/Layout/default/Address/Form.php
+++ b/Layout/default/Address/Form.php
@@ -23,7 +23,7 @@
               <li class="breadcrumb-item"><a href="<?=self::getUrl("Dashboard")?>"><?=MFAPPNAME_SLUG?></a></li>
               <li class="breadcrumb-item"><a href="<?=self::getUrl("Address")?>">Personen & Firmen</a></li>
               <?php if($address->id): ?>
-              <li class="breadcrumb-item"><a href="<?=self::getUrl("Address", "View", ['id' => $address->id])?>"><?=$address->getCompanyOrName()?> [<?=$address->customer_number?>]</a></li>
+              <li class="breadcrumb-item"><a href="<?=self::getUrl("Address", "View", ['id' => $address->id])?>"><?=(is_object($address) && get_class($address) == "Address") ? $address->getCompanyOrName() : ""?> [<?=$address->customer_number?>]</a></li>
               <?php endif; ?>
               <li class="breadcrumb-item active"><?=($address->id) ? "bearbeiten" : "Neu" ?></li>
             </ol>
@@ -169,7 +169,7 @@
                 </div>
               </div>
               
-              <h4>Verrechnungsdaten</h4>
+              <h4 id="billing-data">Verrechnungsdaten</h4>
               <div class="card">
                 <div class="card-body">
                   <div class="form-group row">
@@ -228,6 +228,11 @@
                     </div>
                   </div>
                   
+                  <div class="form-group row">
+                    <label class="col-lg-2 col-form-label" for="bank_account_bic"></label>
+                    <div class="col-lg-10 alert alert-danger hidden" id="bank-error"></div>
+                  </div>
+                  
                   
                 </div>
               </div>
@@ -400,6 +405,9 @@
 
 
 <script type="text/javascript">
+  
+  var bankdata_valid = false;
+  
   $("#parent_id").select2({
     allowClear: true,
     placeholder: ""
@@ -407,9 +415,7 @@
   $("#addresstypes").select2();
   
   
-  
-  
-  function validateIban(iban) {
+  function validateIbanFormat(iban) {
     if(!iban) {
       return false;
     }
@@ -446,15 +452,87 @@
     }
   }
   
+  function validateIbanBic(iban, bic) {
+    if(!iban) return false;
+    iban = iban.toUpperCase().replace(/\s+/, '');
+    
+    $.post("<?=self::getUrl("Address", "api")?>", {
+        do: "validateIbanBic",
+        iban: iban,
+        bic: bic
+      },
+      function(success) {
+        if(success.status == "OK") {
+          var data = success.result;
+          $("#bank-error").hide();
+          $("#bank-error").text("");
+          
+          if(data.iban_correct && !data.iban_sus && data.bic_correct) {
+            bankdata_valid = true;
+            $('#addressForm').submit();
+            return;
+          }
+          
+          var bank_error = [];
+          
+          if(!data.iban_correct) {
+            $("#bank_account_iban").addClass("invalid");
+            bank_error.push("Ungültige IBAN!");
+          }
+          if(data.iban_sus) {
+            $("#bank_account_iban").addClass("invalid");
+            bank_error.push("IBAN verdächtig (" + data.iban_sus + ")!");
+          }
+          if(!data.bic_correct) {
+            $("#bank_account_bic").addClass("invalid");
+            bank_error.push("Ungültige BIC!");
+            if(Array.isArray(data.bic)) {
+              bank_error.push(" Mögliche korrekte BIC: " + data.bic.join(", "));
+            }
+          }
+          
+          $("#bank-error").html(bank_error.join("<br />\n"));
+          $("#bank-error").show();
+          $('html, body').animate( {scrollTop: $('#billing-data').offset().top - 230}, 200);
+          
+          
+          
+        } else {
+          $("#bank-error").text("Beim Validieren der Bankdaten ist ein Fehler aufgetreten.");
+        }
+      },
+      "json"
+    );
+    
+    
+    return false;
+  }
+  
   $('#addressForm').submit(function(e) {
     $("#error").hide();
-    if($('#billing_type').val() == "sepa" &&  !validateIban($("#bank_account_iban").val())) {
-      $("#error").show();
-      console.log("nope");
+    $("#bank-error").hide();
+    
+    if($('#billing_type').val() == "sepa") {
+      console.log("bankdata_valid (1): " + bankdata_valid);
+      if(bankdata_valid) {
+        return true;
+      }
+      
+      if(!validateIbanFormat($("#bank_account_iban").val())) {
+        $("#error").show();
+        console.log("nope");
+      }
+      
+      console.log("bankdata_valid: " + bankdata_valid);
+      if($("#bank_account_iban").val() != "<?=$address->bank_account_iban?>" || $("#bank_account_bic").val() != "<?=$address->bank_account_bic?>") {
+        validateIbanBic($("#bank_account_iban").val(), $("#bank_account_bic").val());
+      } else {
+        return true;
+      }
+
       e.preventDefault();
       return false;
     }
-    return true;
   });
   
   
diff --git a/application/Address/AddressController.php b/application/Address/AddressController.php
index 10d036bfc..0be42eee9 100644
--- a/application/Address/AddressController.php
+++ b/application/Address/AddressController.php
@@ -686,47 +686,13 @@ class AddressController extends mfBaseController {
       return false;
     }
     
-    $creds = TT_IBAN_VALIDATOR_USER.":".TT_IBAN_VALIDATOR_PASS;
-    $b64creds = base64_encode($creds);
-    
-    $ctx = stream_context_create([
-      "http" => [
-        "header" => "Authorization: Basic $b64creds"
-      ]
-    ]);
-    
-    $url = TT_IBAN_VALIDATOR_BASEURL.$iban;
-    $resp = file_get_contents($url, false, $ctx);
-    
-    if($resp) {
-      $data = json_decode($resp);
+    $result = IbanValidator::validate($iban, $bic);
+    if(is_array($result) && $result) {
+      return $result;
     }
     
-    $iban_correct = false;
-    $iban_sus = false;
-    $bic_correct = false;
-    $potential_bics = [];
+    return false;
     
-    if($data->result == "passed") {
-      $iban_correct = true;
-    }
-    
-    if(is_array($data->all_bic_candidates) && count($data->all_bic_candidates)) {
-      foreach($data->all_bic_candidates as $bic_candidate) {
-        if(!$bic_candidate->bic) continue;
-        $potential_bics[] = $bic_candidate->bic;
-        
-        if($bic_candidate->bic == $bic) {
-          $bic_correct = true;
-        }
-      }
-    }
-    
-    if($data->iban_listed) {
-      $iban_sus = $data->iban_listed;
-    }
-    
-    return ["iban" => $data->iban, "bic" => $potential_bics, "iban_correct" => $iban_correct, "iban_sus" => $iban_sus, "bic_correct" => $bic_correct];
   }
   
 
diff --git a/lib/IbanValidator/IbanValidator.php b/lib/IbanValidator/IbanValidator.php
new file mode 100644
index 000000000..2d2fd2790
--- /dev/null
+++ b/lib/IbanValidator/IbanValidator.php
@@ -0,0 +1,57 @@
+<?php
+
+class IbanValidator {
+  
+  public static function validate($iban, $bic = false) {
+    if(!$iban) {
+      return false;
+    }
+    
+    $creds = TT_IBAN_VALIDATOR_USER.":".TT_IBAN_VALIDATOR_PASS;
+    $b64creds = base64_encode($creds);
+    
+    $ctx = stream_context_create([
+      "http" => [
+        "header" => "Authorization: Basic $b64creds"
+      ]
+    ]);
+    
+    $url = TT_IBAN_VALIDATOR_BASEURL.$iban;
+    $resp = file_get_contents($url, false, $ctx);
+    
+    if($resp) {
+      $data = json_decode($resp);
+    }
+    
+    $iban_correct = false;
+    $iban_sus = false;
+    $bic_correct = false;
+    $potential_bics = [];
+    $bank = false;
+    
+    if($data->result == "passed") {
+      $iban_correct = true;
+    }
+    
+    if(is_array($data->all_bic_candidates) && count($data->all_bic_candidates)) {
+      foreach($data->all_bic_candidates as $bic_candidate) {
+        if(!$bic_candidate->bic) continue;
+        $potential_bics[] = $bic_candidate->bic;
+        
+        if($bic_candidate->bic == $bic) {
+          $bic_correct = true;
+        }
+      }
+    }
+    
+    if($data->iban_listed) {
+      $iban_sus = $data->iban_listed;
+    }
+    
+    if($data->bank) {
+      $bank = $data->bank;
+    }
+    
+    return ["bank" => $bank, "iban" => $data->iban, "bic" => $potential_bics, "iban_correct" => $iban_correct, "iban_sus" => $iban_sus, "bic_correct" => $bic_correct];
+  }
+}
\ No newline at end of file