diff --git a/syntax/ats.vim b/syntax/ats.vim
index adf5b46..6903641 100644
--- a/syntax/ats.vim
+++ b/syntax/ats.vim
@@ -56,7 +56,7 @@ syntax match logicalOr '||' conceal cchar=∨
 
 syn match atsChar "\v'.'"
 syn match atsChar "\v'.*'" contains=atsSpecial
-syn match atsSpecial "\v'("
+syn match atsSpecial "\v'\("
 
 syn include @c syntax/c.vim
 syn region cBlock matchgroup=atsCBlock start="%{\|%{^\|%{#" end="%}" contains=@c