diff --git a/java/src/org/broadinstitute/sting/gatk/traversals/TraverseByLoci.java b/java/src/org/broadinstitute/sting/gatk/traversals/TraverseByLoci.java
index 99e5c5d45..3c74e00da 100644
--- a/java/src/org/broadinstitute/sting/gatk/traversals/TraverseByLoci.java
+++ b/java/src/org/broadinstitute/sting/gatk/traversals/TraverseByLoci.java
@@ -120,7 +120,7 @@ public class TraverseByLoci extends TraversalEngine {
                 // Iterate forward to get all reference ordered data covering this locus
                 final List<ReferenceOrderedDatum> rodData = getReferenceOrderedDataAtLocus(rodIters, locus.getLocation());
 
-                walkAtLocus( walker, sum, locus, refSite, rodData );
+                sum = walkAtLocus( walker, sum, locus, refSite, rodData );
 
                 //System.out.format("Working at %s\n", locus.getLocation().toString());
 
@@ -158,4 +158,4 @@ public class TraverseByLoci extends TraversalEngine {
         printProgress("loci", locus.getLocation());
         return sum;
     }
-}
\ No newline at end of file
+}