diff --git a/koha-tmpl/intranet-tmpl/prog/en/modules/reports/guided_reports_start.tt b/koha-tmpl/intranet-tmpl/prog/en/modules/reports/guided_reports_start.tt
index 881ca02334..dfc3b1d2b7 100644
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/reports/guided_reports_start.tt
+++ b/koha-tmpl/intranet-tmpl/prog/en/modules/reports/guided_reports_start.tt
@@ -882,7 +882,7 @@
                                                 <label for="sql_params_[% sql_param.labelid | html %]">[% sql_param.entry | html %]:</label>
                                                 [% IF (sql_param.select_multiple) %]
                                                     <select name="[%- sql_param.input.name | html -%]" tabindex="1"  id="[%- sql_param.input.id | html -%]" multiple>
-                                                        <option value="null" hidden></option>
+                                                        <option value="%" hidden></option>
                                                 [% ELSE %]
                                                     <select name="[%- sql_param.input.name | html -%]" tabindex="1"  id="[%- sql_param.input.id | html -%]">
                                                 [% END %]
@@ -1585,8 +1585,13 @@
 
             $('#report_param_form').on('submit', function(e) {
                 $('#report_param_form').find('select[multiple]').each( function (i) {
-                    var $selected = $('option:first', this).val();
-                    $(this).val($selected);
+                    if( $(this).find('option:selected').length === 0 ) {
+                        $(this).val(['%']);
+                    }
+                    else if( $(this).find('option:selected').length > 1 ) {
+                        var $selected = $('option:first', this).val();
+                        $(this).val($selected);
+                    }
                 });
             });
         }