diff --git a/libatrade.cabal b/libatrade.cabal
index cdd81aa..bc0b522 100644
--- a/libatrade.cabal
+++ b/libatrade.cabal
@@ -36,6 +36,7 @@ library
                      , zeromq4-haskell
                      , unordered-containers
                      , containers
+                     , monad-loops
   default-language:    Haskell2010
 
 executable libatrade-exe
diff --git a/src/ATrade/Broker/Server.hs b/src/ATrade/Broker/Server.hs
index cd5a0e7..35cda5d 100644
--- a/src/ATrade/Broker/Server.hs
+++ b/src/ATrade/Broker/Server.hs
@@ -11,16 +11,18 @@ import ATrade.Broker.Protocol
 import System.ZMQ4
 import Data.List.NonEmpty
 import qualified Data.Map as M
-import qualified Data.ByteString as B
-import qualified Data.ByteString.Lazy as BL
+import qualified Data.ByteString as B hiding (putStrLn)
+import qualified Data.ByteString.Lazy as BL hiding (putStrLn)
 import qualified Data.Text as T
 import qualified Data.List as L
 import Data.Aeson
+import Data.Maybe
 import Data.Time.Clock
 import Data.IORef
 import Control.Concurrent
 import Control.Exception
 import Control.Monad
+import Control.Monad.Loops
 import System.Log.Logger
 import ATrade.Util
 
@@ -43,10 +45,11 @@ data BrokerServerState = BrokerServerState {
   pendingNotifications :: M.Map PeerId [Notification],
   brokers :: [BrokerInterface],
   completionMvar :: MVar (),
+  killMvar :: MVar (),
   orderIdCounter :: OrderId
 }
 
-data BrokerServerHandle = BrokerServerHandle ThreadId (MVar ())
+data BrokerServerHandle = BrokerServerHandle ThreadId (MVar ()) (MVar ())
 
 startBrokerServer :: [BrokerInterface] -> Context -> T.Text -> IO BrokerServerHandle
 startBrokerServer brokers c ep = do
@@ -54,6 +57,7 @@ startBrokerServer brokers c ep = do
   bind sock (T.unpack ep)
   tid <- myThreadId
   compMv <- newEmptyMVar
+  killMv <- newEmptyMVar
   state <- newIORef BrokerServerState {
     bsSocket = sock,
     orderMap = M.empty,
@@ -62,12 +66,13 @@ startBrokerServer brokers c ep = do
     pendingNotifications = M.empty,
     brokers = brokers,
     completionMvar = compMv,
+    killMvar = killMv,
     orderIdCounter = 1
   }
   mapM_ (\bro -> setNotificationCallback bro (Just $ notificationCallback state)) brokers
 
   debugM "Broker.Server" "Forking broker server thread"
-  BrokerServerHandle <$> forkIO (brokerServerThread state) <*> pure compMv
+  BrokerServerHandle <$> forkIO (brokerServerThread state) <*> pure compMv <*> pure killMv
 
 notificationCallback :: IORef BrokerServerState -> Notification -> IO ()
 notificationCallback state n = do
@@ -82,9 +87,10 @@ notificationCallback state n = do
         Just ns -> s { pendingNotifications = M.insert peerId (n : ns) (pendingNotifications s)}
         Nothing -> s { pendingNotifications = M.insert peerId [n] (pendingNotifications s)})
 
+brokerServerThread :: IORef BrokerServerState -> IO ()
 brokerServerThread state = finally brokerServerThread' cleanup
   where
-    brokerServerThread' = forever $ do
+    brokerServerThread' = whileM_ (fmap killMvar (readIORef state) >>= fmap isNothing . tryTakeMVar) $ do
       sock <- bsSocket <$> readIORef state
       evs <- poll 200 [Sock sock [In] Nothing] 
       when ((L.length . L.head) evs > 0) $ do
@@ -121,6 +127,7 @@ brokerServerThread state = finally brokerServerThread' cleanup
     cleanup = do
       sock <- bsSocket <$> readIORef state
       close sock
+
       mv <- completionMvar <$> readIORef state
       putMVar mv ()
 
@@ -161,5 +168,7 @@ brokerServerThread state = finally brokerServerThread' cleanup
 
 
 stopBrokerServer :: BrokerServerHandle -> IO ()
-stopBrokerServer (BrokerServerHandle tid compMv) = yield >> killThread tid >> readMVar compMv
+stopBrokerServer (BrokerServerHandle tid compMv killMv) = do
+  putMVar killMv ()
+  yield >> readMVar compMv
 
diff --git a/src/ATrade/Types.hs b/src/ATrade/Types.hs
index a5a7bfa..4129006 100644
--- a/src/ATrade/Types.hs
+++ b/src/ATrade/Types.hs
@@ -71,11 +71,11 @@ instance Enum DataType where
     | otherwise = Unknown
 
 data Tick = Tick {
-  security :: T.Text,
-  datatype :: DataType,
-  timestamp :: UTCTime,
-  value :: Decimal,
-  volume :: Integer
+  security :: !T.Text,
+  datatype :: !DataType,
+  timestamp :: !UTCTime,
+  value :: !Decimal,
+  volume :: !Integer
 } deriving (Show, Eq)
 
 serializeTick :: Tick -> [ByteString]