diff --git a/hledger-lib/Hledger/Data/Account.hs b/hledger-lib/Hledger/Data/Account.hs
index 64cfbaf0a..e1dc82415 100644
--- a/hledger-lib/Hledger/Data/Account.hs
+++ b/hledger-lib/Hledger/Data/Account.hs
@@ -10,6 +10,7 @@ account, and subaccounting-excluding and -including balances.
 module Hledger.Data.Account
 where
 import Data.List
+import Data.List.Extra (groupSort, groupOn)
 import Data.Maybe
 import Data.Ord
 import qualified Data.Map as M
@@ -63,10 +64,9 @@ nullacct = Account
 accountsFromPostings :: [Posting] -> [Account]
 accountsFromPostings ps =
   let
-    acctamts = [(paccount p,pamount p) | p <- ps]
-    grouped = groupBy (\a b -> fst a == fst b) $ sort $ acctamts
-    counted = [(a, length acctamts) | acctamts@((a,_):_) <- grouped]
-    summed = map (\as@((aname,_):_) -> (aname, sumStrict $ map snd as)) grouped -- always non-empty
+    grouped = groupSort [(paccount p,pamount p) | p <- ps]
+    counted = [(aname, length amts) | (aname, amts) <- grouped]
+    summed =  [(aname, sumStrict amts) | (aname, amts) <- grouped]  -- always non-empty
     nametree = treeFromPaths $ map (expandAccountName . fst) summed
     acctswithnames = nameTreeToAccount "root" nametree
     acctswithnumps = mapAccounts setnumps    acctswithnames where setnumps    a = a{anumpostings=fromMaybe 0 $ lookup (aname a) counted}
@@ -132,7 +132,7 @@ clipAccountsAndAggregate d as = combined
     where
       clipped  = [a{aname=clipOrEllipsifyAccountName d $ aname a} | a <- as]
       combined = [a{aebalance=sum (map aebalance same)}
-                  | same@(a:_) <- groupBy (\a1 a2 -> aname a1 == aname a2) clipped]
+                 | same@(a:_) <- groupOn aname clipped]
 {-
 test cases, assuming d=1:
 
diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index 672b4e3c4..520ee942b 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -75,6 +75,7 @@ import Data.Array.ST
 import Data.Functor.Identity (Identity(..))
 import qualified Data.HashTable.ST.Cuckoo as HT
 import Data.List
+import Data.List.Extra (groupSort)
 -- import Data.Map (findWithDefault)
 import Data.Maybe
 import Data.Monoid
@@ -752,8 +753,7 @@ journalInferCommodityStyles j =
 commodityStylesFromAmounts :: [Amount] -> M.Map CommoditySymbol AmountStyle
 commodityStylesFromAmounts amts = M.fromList commstyles
   where
-    samecomm = \a1 a2 -> acommodity a1 == acommodity a2
-    commamts = [(acommodity $ head as, as) | as <- groupBy samecomm $ sortBy (comparing acommodity) amts]
+    commamts = groupSort [(acommodity as, as) | as <- amts]
     commstyles = [(c, canonicalStyleFrom $ map astyle as) | (c,as) <- commamts]
 
 -- | Given an ordered list of amount styles, choose a canonical style.