diff --git a/moses-chart-cmd/src/IOWrapper.cpp b/moses-chart-cmd/src/IOWrapper.cpp
index 7f246205a..c52eea3df 100644
--- a/moses-chart-cmd/src/IOWrapper.cpp
+++ b/moses-chart-cmd/src/IOWrapper.cpp
@@ -384,7 +384,7 @@ void IOWrapper::OutputNBestList(const ChartTrellisPathList &nBestList, const Cha
 
     // word penalty
     if (labeledOutput)
-      out << "w: ";
+      out << " w: ";
     out << path.GetScoreBreakdown().GetScoreForProducer(system->GetWordPenaltyProducer()) << " ";
 
     // generation