diff --git a/Library/Homebrew/cmd/audit.rb b/Library/Homebrew/cmd/audit.rb
index f786946143..3202bd068c 100755
--- a/Library/Homebrew/cmd/audit.rb
+++ b/Library/Homebrew/cmd/audit.rb
@@ -294,6 +294,11 @@ module Homebrew extend self
 
     ff.each do |f|
       problems = []
+
+      if f.unstable and f.stable.nil?
+        problems += [' * head-only formula']
+      end
+
       problems += audit_formula_instance f
       problems += audit_formula_urls f