diff --git a/com.ibm.wala.util/src/com/ibm/wala/fixpoint/BitVectorVariable.java b/com.ibm.wala.util/src/com/ibm/wala/fixpoint/BitVectorVariable.java
index 59efcb9e9..4956e8377 100644
--- a/com.ibm.wala.util/src/com/ibm/wala/fixpoint/BitVectorVariable.java
+++ b/com.ibm.wala.util/src/com/ibm/wala/fixpoint/BitVectorVariable.java
@@ -42,6 +42,8 @@ public class BitVectorVariable extends AbstractVariable<BitVectorVariable> {
     }
     if (other.V != null) {
       V.copySet(other.V);
+    } else {
+      V = null;
     }
   }