diff --git a/hledger-api/hledger-api.hs b/hledger-api/hledger-api.hs
index 26ef58f13..32bfb08c0 100644
--- a/hledger-api/hledger-api.hs
+++ b/hledger-api/hledger-api.hs
@@ -104,7 +104,7 @@ type HledgerApi =
          "accountnames" :> Get '[JSON] [AccountName]
     :<|> "transactions" :> Get '[JSON] [Transaction]
     :<|> "prices"       :> Get '[JSON] [MarketPrice]
-    :<|> "commodities"  :> Get '[JSON] [Commodity]
+    :<|> "commodities"  :> Get '[JSON] [CommoditySymbol]
     :<|> "accounts"     :> Get '[JSON] [Account]
     :<|> "accounts"     :> Capture "acct" AccountName :> Get '[JSON] AccountTransactionsReport
     )
diff --git a/hledger-lib/Hledger/Data/Amount.hs b/hledger-lib/Hledger/Data/Amount.hs
index 2bca8cba8..f45cbc3c7 100644
--- a/hledger-lib/Hledger/Data/Amount.hs
+++ b/hledger-lib/Hledger/Data/Amount.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE CPP, StandaloneDeriving, RecordWildCards #-}
 {-|
 A simple 'Amount' is some quantity of money, shares, or anything else.
-It has a (possibly null) 'Commodity' and a numeric quantity:
+It has a (possibly null) 'CommoditySymbol' and a numeric quantity:
 
 @
   $1
@@ -180,7 +180,7 @@ similarAmountsOp op Amount{acommodity=_,  aquantity=q1, astyle=AmountStyle{aspre
 
 -- | Convert an amount to the specified commodity, ignoring and discarding
 -- any assigned prices and assuming an exchange rate of 1.
-amountWithCommodity :: Commodity -> Amount -> Amount
+amountWithCommodity :: CommoditySymbol -> Amount -> Amount
 amountWithCommodity c a = a{acommodity=c, aprice=NoPrice}
 
 -- | Convert an amount to the commodity of its assigned price, if any.  Notes:
@@ -340,7 +340,7 @@ maxprecisionwithpoint = 999999
 
 -- like journalCanonicaliseAmounts
 -- | Canonicalise an amount's display style using the provided commodity style map.
-canonicaliseAmount :: M.Map Commodity AmountStyle -> Amount -> Amount
+canonicaliseAmount :: M.Map CommoditySymbol AmountStyle -> Amount -> Amount
 canonicaliseAmount styles a@Amount{acommodity=c, astyle=s} = a{astyle=s'}
     where
       s' = findWithDefault s c styles
@@ -468,7 +468,7 @@ filterMixedAmount p (Mixed as) = Mixed $ filter p as
 -- with the specified commodity and the quantity of that commodity
 -- found in the original. NB if Amount's quantity is zero it will be
 -- discarded next time the MixedAmount gets normalised.
-filterMixedAmountByCommodity :: Commodity -> MixedAmount -> MixedAmount
+filterMixedAmountByCommodity :: CommoditySymbol -> MixedAmount -> MixedAmount
 filterMixedAmountByCommodity c (Mixed as) = Mixed as'
   where
     as' = case filter ((==c) . acommodity) as of
@@ -580,7 +580,7 @@ showMixedAmountOneLineWithoutPrice m = concat $ intersperse ", " $ map showAmoun
       stripPrices (Mixed as) = Mixed $ map stripprice as where stripprice a = a{aprice=NoPrice}
 
 -- | Canonicalise a mixed amount's display styles using the provided commodity style map.
-canonicaliseMixedAmount :: M.Map Commodity AmountStyle -> MixedAmount -> MixedAmount
+canonicaliseMixedAmount :: M.Map CommoditySymbol AmountStyle -> MixedAmount -> MixedAmount
 canonicaliseMixedAmount styles (Mixed as) = Mixed $ map (canonicaliseAmount styles) as
 
 -------------------------------------------------------------------------------
diff --git a/hledger-lib/Hledger/Data/Commodity.hs b/hledger-lib/Hledger/Data/Commodity.hs
index b516417cb..814b94bf9 100644
--- a/hledger-lib/Hledger/Data/Commodity.hs
+++ b/hledger-lib/Hledger/Data/Commodity.hs
@@ -42,18 +42,18 @@ commoditysymbols =
   ]
 
 -- | Look up one of the sample commodities' symbol by name.
-comm :: String -> Commodity
+comm :: String -> CommoditySymbol
 comm name = snd $ fromMaybe
               (error' "commodity lookup failed")
               (find (\n -> fst n == name) commoditysymbols)
 
 -- | Find the conversion rate between two commodities. Currently returns 1.
-conversionRate :: Commodity -> Commodity -> Double
+conversionRate :: CommoditySymbol -> CommoditySymbol -> Double
 conversionRate _ _ = 1
 
 -- -- | Convert a list of commodities to a map from commodity symbols to
 -- -- unique, display-preference-canonicalised commodities.
--- canonicaliseCommodities :: [Commodity] -> Map.Map String Commodity
+-- canonicaliseCommodities :: [CommoditySymbol] -> Map.Map String CommoditySymbol
 -- canonicaliseCommodities cs =
 --     Map.fromList [(s,firstc{precision=maxp}) | s <- symbols,
 --                   let cs = commoditymap ! s,
diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index 8ca15ec84..8cdeeed00 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -534,7 +534,7 @@ journalApplyCommodityStyles j@Journal{jtxns=ts, jmarketprices=mps} = j''
       fixamount a@Amount{acommodity=c} = a{astyle=journalCommodityStyle j' c}
 
 -- | Get this journal's standard display style for the given commodity, or the null style.
-journalCommodityStyle :: Journal -> Commodity -> AmountStyle
+journalCommodityStyle :: Journal -> CommoditySymbol -> AmountStyle
 journalCommodityStyle j c = M.findWithDefault amountstyle c $ jcommoditystyles j
 
 -- | Choose a standard display style for each commodity.
@@ -552,7 +552,7 @@ journalChooseCommodityStyles j =
 
 -- | Given a list of amounts in parse order, build a map from their commodity names
 -- to standard commodity display formats.
-commodityStylesFromAmounts :: [Amount] -> M.Map Commodity AmountStyle
+commodityStylesFromAmounts :: [Amount] -> M.Map CommoditySymbol AmountStyle
 commodityStylesFromAmounts amts = M.fromList commstyles
   where
     samecomm = \a1 a2 -> acommodity a1 == acommodity a2
@@ -591,8 +591,8 @@ canonicalStyleFrom ss@(first:_) =
 
 -- -- | Get the price for a commodity on the specified day from the price database, if known.
 -- -- Does only one lookup step, ie will not look up the price of a price.
--- journalMarketPriceFor :: Journal -> Day -> Commodity -> Maybe MixedAmount
--- journalMarketPriceFor j d Commodity{symbol=s} = do
+-- journalMarketPriceFor :: Journal -> Day -> CommoditySymbol -> Maybe MixedAmount
+-- journalMarketPriceFor j d CommoditySymbol{symbol=s} = do
 --   let ps = reverse $ filter ((<= d).mpdate) $ filter ((s==).hsymbol) $ sortBy (comparing mpdate) $ jmarketprices j
 --   case ps of (MarketPrice{mpamount=a}:_) -> Just a
 --              _ -> Nothing
@@ -613,19 +613,19 @@ journalConvertAmountsToCost j@Journal{jtxns=ts} = j{jtxns=map fixtransaction ts}
       fixamount = canonicaliseAmount (jcommoditystyles j) . costOfAmount
 
 -- -- | Get this journal's unique, display-preference-canonicalised commodities, by symbol.
--- journalCanonicalCommodities :: Journal -> M.Map String Commodity
+-- journalCanonicalCommodities :: Journal -> M.Map String CommoditySymbol
 -- journalCanonicalCommodities j = canonicaliseCommodities $ journalAmountCommodities j
 
 -- -- | Get all this journal's amounts' commodities, in the order parsed.
--- journalAmountCommodities :: Journal -> [Commodity]
+-- journalAmountCommodities :: Journal -> [CommoditySymbol]
 -- journalAmountCommodities = map acommodity . concatMap amounts . journalAmounts
 
 -- -- | Get all this journal's amount and price commodities, in the order parsed.
--- journalAmountAndPriceCommodities :: Journal -> [Commodity]
+-- journalAmountAndPriceCommodities :: Journal -> [CommoditySymbol]
 -- journalAmountAndPriceCommodities = concatMap amountCommodities . concatMap amounts . journalAmounts
 
 -- -- | Get this amount's commodity and any commodities referenced in its price.
--- amountCommodities :: Amount -> [Commodity]
+-- amountCommodities :: Amount -> [CommoditySymbol]
 -- amountCommodities Amount{acommodity=c,aprice=p} =
 --     case p of Nothing -> [c]
 --               Just (UnitPrice ma)  -> c:(concatMap amountCommodities $ amounts ma)
diff --git a/hledger-lib/Hledger/Data/Ledger.hs b/hledger-lib/Hledger/Data/Ledger.hs
index 14fdba783..124f3b334 100644
--- a/hledger-lib/Hledger/Data/Ledger.hs
+++ b/hledger-lib/Hledger/Data/Ledger.hs
@@ -84,7 +84,7 @@ ledgerDateSpan :: Ledger -> DateSpan
 ledgerDateSpan = postingsDateSpan . ledgerPostings
 
 -- | All commodities used in this ledger.
-ledgerCommodities :: Ledger -> [Commodity]
+ledgerCommodities :: Ledger -> [CommoditySymbol]
 ledgerCommodities = M.keys . jcommoditystyles . ljournal
 
 
diff --git a/hledger-lib/Hledger/Data/Transaction.hs b/hledger-lib/Hledger/Data/Transaction.hs
index 0ba939025..bb906ef30 100644
--- a/hledger-lib/Hledger/Data/Transaction.hs
+++ b/hledger-lib/Hledger/Data/Transaction.hs
@@ -270,7 +270,7 @@ transactionPostingBalances t = (sumPostings $ realPostings t
 -- | Is this transaction balanced ? A balanced transaction's real
 -- (non-virtual) postings sum to 0, and any balanced virtual postings
 -- also sum to 0.
-isTransactionBalanced :: Maybe (Map.Map Commodity AmountStyle) -> Transaction -> Bool
+isTransactionBalanced :: Maybe (Map.Map CommoditySymbol AmountStyle) -> Transaction -> Bool
 isTransactionBalanced styles t =
     -- isReallyZeroMixedAmountCost rsum && isReallyZeroMixedAmountCost bvsum
     isZeroMixedAmount rsum' && isZeroMixedAmount bvsum'
@@ -284,7 +284,7 @@ isTransactionBalanced styles t =
 -- amount or conversion price(s), or return an error message.
 -- Balancing is affected by commodity display precisions, so those can
 -- (optionally) be provided.
-balanceTransaction :: Maybe (Map.Map Commodity AmountStyle) -> Transaction -> Either String Transaction
+balanceTransaction :: Maybe (Map.Map CommoditySymbol AmountStyle) -> Transaction -> Either String Transaction
 balanceTransaction styles t =
   case inferBalancingAmount t of
     Left err -> Left err
diff --git a/hledger-lib/Hledger/Data/Types.hs b/hledger-lib/Hledger/Data/Types.hs
index e1955a5c8..1f51d4132 100644
--- a/hledger-lib/Hledger/Data/Types.hs
+++ b/hledger-lib/Hledger/Data/Types.hs
@@ -64,8 +64,6 @@ data Side = L | R deriving (Eq,Show,Read,Ord,Typeable,Data,Generic)
 
 instance NFData Side
 
-type Commodity = String
-
 -- | The basic numeric type used in amounts. Different implementations
 -- can be selected via cabal flag for testing and benchmarking purposes.
 numberRepresentation :: String
@@ -111,8 +109,15 @@ data DigitGroupStyle = DigitGroups Char [Int]
 
 instance NFData DigitGroupStyle
 
+type CommoditySymbol = String
+
+data Commodity = Commodity {
+  csymbol :: CommoditySymbol,
+  cformat :: Maybe AmountStyle
+  } -- deriving (Eq,Ord,Typeable,Data,Generic)
+
 data Amount = Amount {
-      acommodity :: Commodity,
+      acommodity :: CommoditySymbol,
       aquantity :: Quantity,
       aprice :: Price,                -- ^ the (fixed) price for this amount, if any
       astyle :: AmountStyle
@@ -217,7 +222,7 @@ instance NFData TimeclockEntry
 
 data MarketPrice = MarketPrice {
       mpdate :: Day,
-      mpcommodity :: Commodity,
+      mpcommodity :: CommoditySymbol,
       mpamount :: Amount
     } deriving (Eq,Ord,Typeable,Data,Generic) -- & Show (in Amount.hs)
 
@@ -231,7 +236,7 @@ type Year = Integer
 -- is saved for later use by eg the add command.
 data JournalContext = Ctx {
       ctxYear      :: !(Maybe Year)      -- ^ the default year most recently specified with Y
-    , ctxDefaultCommodityAndStyle :: !(Maybe (Commodity,AmountStyle)) -- ^ the default commodity and amount style most recently specified with D
+    , ctxDefaultCommodityAndStyle :: !(Maybe (CommoditySymbol,AmountStyle)) -- ^ the default commodity and amount style most recently specified with D
     , ctxAccounts :: ![AccountName]      -- ^ the accounts that have been defined with account directives so far
     , ctxParentAccount :: ![AccountName] -- ^ the current stack of parent accounts/account name components
                                          --   specified with "apply account" directive(s). Concatenated, these
@@ -261,7 +266,7 @@ data Journal = Journal {
                                             -- first followed by any included files in the
                                             -- order encountered.
       filereadtime :: ClockTime,            -- ^ when this journal was last read from its file(s)
-      jcommoditystyles :: M.Map Commodity AmountStyle  -- ^ how to display amounts in each commodity
+      jcommoditystyles :: M.Map CommoditySymbol AmountStyle  -- ^ how to display amounts in each commodity
     } deriving (Eq, Typeable, Data, Generic)
 
 instance NFData Journal
diff --git a/hledger-lib/Hledger/Read/JournalReader.hs b/hledger-lib/Hledger/Read/JournalReader.hs
index 41f590518..157b0e576 100644
--- a/hledger-lib/Hledger/Read/JournalReader.hs
+++ b/hledger-lib/Hledger/Read/JournalReader.hs
@@ -232,10 +232,10 @@ setYear y = modifyState (\ctx -> ctx{ctxYear=Just y})
 getYear :: Monad m => JournalParser m (Maybe Integer)
 getYear = liftM ctxYear getState
 
-setDefaultCommodityAndStyle :: Monad m => (Commodity,AmountStyle) -> JournalParser m ()
+setDefaultCommodityAndStyle :: Monad m => (CommoditySymbol,AmountStyle) -> JournalParser m ()
 setDefaultCommodityAndStyle cs = modifyState (\ctx -> ctx{ctxDefaultCommodityAndStyle=Just cs})
 
-getDefaultCommodityAndStyle :: Monad m => JournalParser m (Maybe (Commodity,AmountStyle))
+getDefaultCommodityAndStyle :: Monad m => JournalParser m (Maybe (CommoditySymbol,AmountStyle))
 getDefaultCommodityAndStyle = ctxDefaultCommodityAndStyle `fmap` getState
 
 pushAccount :: Monad m => String -> JournalParser m ()
diff --git a/hledger-lib/Hledger/Reports/BalanceReport.hs b/hledger-lib/Hledger/Reports/BalanceReport.hs
index 67c46c1d2..a63d52843 100644
--- a/hledger-lib/Hledger/Reports/BalanceReport.hs
+++ b/hledger-lib/Hledger/Reports/BalanceReport.hs
@@ -156,7 +156,7 @@ amountValue j d a =
 -- the given date, in the commodity in which it has most recently been
 -- market-priced (ie the commodity mentioned in the most recent
 -- applicable historical price directive before this date).
-commodityValue :: Journal -> Day -> Commodity -> Maybe Amount
+commodityValue :: Journal -> Day -> CommoditySymbol -> Maybe Amount
 commodityValue j d c
     | null applicableprices = Nothing
     | otherwise             = Just $ mpamount $ last applicableprices
diff --git a/hledger-lib/Hledger/Reports/TransactionsReports.hs b/hledger-lib/Hledger/Reports/TransactionsReports.hs
index 888678550..bdd72c092 100644
--- a/hledger-lib/Hledger/Reports/TransactionsReports.hs
+++ b/hledger-lib/Hledger/Reports/TransactionsReports.hs
@@ -217,7 +217,7 @@ filterTransactionPostings m t@Transaction{tpostings=ps} = t{tpostings=filter (m
 
 -- | Split a transactions report whose items may involve several commodities,
 -- into one or more single-commodity transactions reports.
-transactionsReportByCommodity :: TransactionsReport -> [(Commodity, TransactionsReport)]
+transactionsReportByCommodity :: TransactionsReport -> [(CommoditySymbol, TransactionsReport)]
 transactionsReportByCommodity tr =
   [(c, filterTransactionsReportByCommodity c tr) | c <- transactionsReportCommodities tr]
   where
@@ -227,7 +227,7 @@ transactionsReportByCommodity tr =
 -- Remove transaction report items and item amount (and running
 -- balance amount) components that don't involve the specified
 -- commodity. Other item fields such as the transaction are left unchanged.
-filterTransactionsReportByCommodity :: Commodity -> TransactionsReport -> TransactionsReport
+filterTransactionsReportByCommodity :: CommoditySymbol -> TransactionsReport -> TransactionsReport
 filterTransactionsReportByCommodity c (label,items) =
   (label, fixTransactionsReportItemBalances $ concat [filterTransactionsReportItemByCommodity c i | i <- items])
   where
diff --git a/hledger-web/Handler/RegisterR.hs b/hledger-web/Handler/RegisterR.hs
index 164f50de8..d9bb8b95e 100644
--- a/hledger-web/Handler/RegisterR.hs
+++ b/hledger-web/Handler/RegisterR.hs
@@ -99,7 +99,7 @@ registerItemsHtml _ vd (balancelabel,items) = [hamlet|
                --                      Data.Foldable.Foldable t1 =>
                --                      t1 (Transaction, t2, t3, t4, t5, MixedAmount)
                --                      -> t -> Text.Blaze.Internal.HtmlM ()
-registerChartHtml :: [(Commodity, (String, [TransactionsReportItem]))] -> HtmlUrl AppRoute
+registerChartHtml :: [(CommoditySymbol, (String, [TransactionsReportItem]))] -> HtmlUrl AppRoute
 registerChartHtml percommoditytxnreports =
  -- have to make sure plot is not called when our container (maincontent)
  -- is hidden, eg with add form toggled
@@ -171,6 +171,6 @@ registerChartHtml percommoditytxnreports =
            of "" -> ""
               s  -> s++":"
    colorForCommodity = fromMaybe 0 . flip lookup commoditiesIndex
-   commoditiesIndex = zip (map fst percommoditytxnreports) [0..] :: [(Commodity,Int)]
+   commoditiesIndex = zip (map fst percommoditytxnreports) [0..] :: [(CommoditySymbol,Int)]
    simpleMixedAmountQuantity = maybe 0 aquantity . headMay . amounts
    shownull c = if null c then " " else c
diff --git a/hledger/Hledger/Cli/Balance.hs b/hledger/Hledger/Cli/Balance.hs
index 24ffde7fa..28fb930f9 100644
--- a/hledger/Hledger/Cli/Balance.hs
+++ b/hledger/Hledger/Cli/Balance.hs
@@ -320,7 +320,7 @@ balance opts@CliOpts{reportopts_=ropts} j = do
 -- in which it has most recently been market-priced, ie the commodity
 -- mentioned in the most recent applicable historical price directive
 -- before this date.
--- defaultValuationCommodity :: Journal -> Day -> Commodity -> Maybe Commodity
+-- defaultValuationCommodity :: Journal -> Day -> CommoditySymbol -> Maybe CommoditySymbol
 -- defaultValuationCommodity j d c = mpamount <$> commodityValue j d c
 
 -- | Render a single-column balance report as CSV.
diff --git a/site/developer-guide.md b/site/developer-guide.md
index f25a5158a..7ac4ac196 100644
--- a/site/developer-guide.md
+++ b/site/developer-guide.md
@@ -926,7 +926,7 @@ Posting -- AccountName
 Account -- "2" MixedAmount
 Posting -- MixedAmount
 MixedAmount *-- "*" Amount
-Amount -- Commodity
+Amount -- CommoditySymbol
 Amount -- Quantity
 Amount -- Price
 Amount -- AmountStyle
@@ -942,7 +942,7 @@ each containing multiple
 of some
 [MixedAmount](http://hackage.haskell.org/package/hledger-lib-0.23.2/docs/Hledger-Data-Types.html#t:MixedAmount)
 (multiple
-single-[Commodity](http://hackage.haskell.org/package/hledger-lib-0.23.2/docs/Hledger-Data-Types.html#t:Commodity)
+single-[CommoditySymbol](http://hackage.haskell.org/package/hledger-lib-0.23.2/docs/Hledger-Data-Types.html#t:CommoditySymbol)
 [Amounts](http://hackage.haskell.org/package/hledger-lib-0.23.2/docs/Hledger-Data-Types.html#t:Amount))
 to some
 [AccountName](http://hackage.haskell.org/package/hledger-lib-0.23.2/docs/Hledger-Data-Types.html#t:AccountName).