diff --git a/src/TransactionBuilder.php b/src/TransactionBuilder.php
index 61fecd5..6ff394d 100644
--- a/src/TransactionBuilder.php
+++ b/src/TransactionBuilder.php
@@ -146,6 +146,18 @@ public function withEntityUseCode($code)
         return $this;
     }
 
+    /**
+     * Set client application customer or usage type
+     *
+     * @param   string              code    (See API endpoint `/api/v2/definitions/entityusecodes` for a list of allowable values)
+     * @return TransactionBuilder
+     */
+    public function withSalesPersonCode($code)
+    {
+        $this->_model['salespersonCode'] = $code;
+        return $this;
+    }
+
     /**
      * Set purchase order number
      *