diff --git a/lib/internal/Magento/Framework/Convert/Excel.php b/lib/internal/Magento/Framework/Convert/Excel.php
index f2a629407c1cf..09acd88b38a7f 100644
--- a/lib/internal/Magento/Framework/Convert/Excel.php
+++ b/lib/internal/Magento/Framework/Convert/Excel.php
@@ -147,6 +147,7 @@ protected function _getXmlRow($row, $useCallback)
             }
             if (isset($value[0]) && in_array($value[0], ['=', '+', '-'])) {
                 $value = ' ' . $value;
+                $dataType = 'String';
             }
 
             $value = str_replace("\r\n", '
', $value);