diff --git a/src/ATrade/Types.hs b/src/ATrade/Types.hs
index 4129006..459afaa 100644
--- a/src/ATrade/Types.hs
+++ b/src/ATrade/Types.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE OverloadedStrings, TypeSynonymInstances, FlexibleInstances #-}
 
 module ATrade.Types (
+  TickerId,
   Tick(..),
   DataType(..),
   serializeTick,
@@ -32,6 +33,8 @@ import Data.Text.Encoding as E
 import Data.Time.Clock
 import Data.Word
 
+type TickerId = T.Text
+
 data DataType = Unknown
   | Price
   | OpenInterest