diff --git a/Main.hs b/Main.hs
--- a/Main.hs
+++ b/Main.hs
@@ -14,6 +14,7 @@
 import Data.List
 import Data.Ord
 import Statistics.Math.RootFinding
+import Data.Decimal
 
 
 import Paths_hledger_irr ( version )
@@ -105,7 +106,7 @@
   when (null (optInvAcc opts)) (commandLineError "required --investment-account option is missing\n")
   when (null (optInterestAcc opts)) (commandLineError "required --interest-account option is missing\n")
   when (length args > 0) (commandLineError "no command line arguments allowed")
-  jnl' <- readJournalFile Nothing Nothing (optInput opts) >>= either fail return
+  jnl' <- readJournalFile Nothing Nothing True (optInput opts) >>= either fail return
 
   let ts = jtxns $ filterJournalTransactions (Acct (optInvAcc opts)) jnl'
   when (null ts) $ do
@@ -148,7 +149,7 @@
 
       -- 0% is always a solution, so require at least something here
       putStr $ printf "%s - %s: " (showDate ibegin) (showDate iend)
-      case ridders 0.00001 (0.000001,1000) (aquantity . interestSum iend totalCF) of
+      case ridders 0.00001 (0.000001,1000) (realToFrac . aquantity . interestSum iend totalCF) of
         Root rate -> putStrLn (printf "%0.2f%%" ((rate-1)*100))
         _ -> putStrLn "Error: Failed to find solution."
 
@@ -169,7 +170,7 @@
 
 -- | Divide an amount's quantity by a constant.
 multiplyAmount :: Amount -> Double -> Amount
-multiplyAmount a@Amount{aquantity=q} d = a{aquantity=q*d}
+multiplyAmount a@Amount{aquantity=q} d = a{aquantity=q *. d}
 
 
 interestSum :: Day -> CashFlow -> Double -> Amount
diff --git a/hledger-irr.cabal b/hledger-irr.cabal
--- a/hledger-irr.cabal
+++ b/hledger-irr.cabal
@@ -1,5 +1,5 @@
 Name:                   hledger-irr
-Version:                0.1.1.4
+Version:                0.1.1.5
 Synopsis:               computes the internal rate of return of an investment
 License:                BSD3
 License-file:           LICENSE
@@ -64,17 +64,17 @@
  > 2011/04/01: €-50.00
  > 2011/05/01: €47.00
  > 2011/06/01: €90.00
- > 2011/01/01 - 2014/05/01: 17.72%
+ > 2011/01/01 - 2015/03/01: -100.00%
  > $ hledger-irr -f speculation.ledger -t "Rate Gain" -i Speculation -e 2011-03-01
- > 2011/01/01 - 2011/03/01: 26.11%
+ > 2011/01/01 - 2011/03/01: 26.12%
  > $ hledger-irr -f speculation.ledger -t "Rate Gain" -i Speculation -b 2011-03-01
- > 2011/03/01 - 2014/05/01: 12.28%
+ > 2011/03/01 - 2015/03/01: -100.00%
  > $ hledger-irr -f speculation.ledger -t "Rate Gain" -i Speculation --monthly
- > 2011/01/01 - 2011/02/01: 12.43%
- > 2011/02/01 - 2011/03/01: 41.57%
- > 2011/03/01 - 2011/04/01: -51.45%
- > 2011/04/01 - 2011/05/01: 32.27%
- > 2011/05/01 - 2011/06/01: 96.01%
+ > 2011/01/01 - 2011/02/01: 12.49%
+ > 2011/02/01 - 2011/03/01: 41.55%
+ > 2011/03/01 - 2011/04/01: -51.44%
+ > 2011/04/01 - 2011/05/01: 32.24%
+ > 2011/05/01 - 2011/06/01: 95.92%
  .
  Running the utility with @--help@ gives a brief overview over the
  available options:
@@ -104,7 +104,7 @@
 
 Executable hledger-irr
   Main-is:              Main.hs
-  Build-depends:        base >= 3 && < 5, hledger-lib == 0.20.* || == 0.21.* || == 0.22.* || == 0.23.*, time, Cabal, statistics >= 0.10
+  Build-depends:        base >= 3 && < 5, hledger-lib >= 0.23.98 && < 0.25, Decimal, time, Cabal, statistics >= 0.10
   Ghc-Options:          -Wall
 
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