diff --git a/hsmw-highlight b/hsmw-highlight
index 0371ed9..eed7ea5 100644
--- a/hsmw-highlight
+++ b/hsmw-highlight
@@ -689,7 +689,7 @@ typeset -gA HSMW_HIGHLIGHT_STYLES
             if [[ ${arg:$i} = (#b)([[:alpha:]_][[:alnum:]_]#|[[:digit:]]##)* ]] ; then
               (( k += ${#match[1]} )) # highlight the parameter name
               (( i += ${#match[1]} )) # skip past it
-            elif [[ ${arg:$i} = (#b)([{](\([a-zA-Z0@]##\))(#c0,1)([[:alpha:]_][[:alnum:]_]#|[[:digit:]]##)[}])* ]] ; then
+            elif [[ ${arg:$i} = (#b)([{](\([a-zA-Z0@%#]##\))(#c0,1)([[:alpha:]_][[:alnum:]_]#|[[:digit:]]##)[}])* ]] ; then
               (( k += ${#match[1]} )) # highlight the parameter name and braces
               (( i += ${#match[1]} )) # skip past it
             else