diff --git a/asterix-om/src/main/java/edu/uci/ics/asterix/builders/OrderedListBuilder.java b/asterix-om/src/main/java/edu/uci/ics/asterix/builders/OrderedListBuilder.java
index a336841..9fb422d 100644
--- a/asterix-om/src/main/java/edu/uci/ics/asterix/builders/OrderedListBuilder.java
+++ b/asterix-om/src/main/java/edu/uci/ics/asterix/builders/OrderedListBuilder.java
@@ -58,7 +58,7 @@
     public void addItem(IValueReference item) throws HyracksDataException {
         if (!fixedSize)
             this.offsets.add((short) outputStream.size());
-        if (itemTypeTag == ATypeTag.ANY || item.getByteArray()[0] == serNullTypeTag) {
+        if (itemTypeTag == ATypeTag.ANY || (itemTypeTag == ATypeTag.NULL && item.getByteArray()[0] == serNullTypeTag)) {
             this.numberOfItems++;
             this.outputStream.write(item.getByteArray(), item.getStartOffset(), item.getLength());
         } else if (item.getByteArray()[0] != serNullTypeTag) {
diff --git a/asterix-om/src/main/java/edu/uci/ics/asterix/builders/UnorderedListBuilder.java b/asterix-om/src/main/java/edu/uci/ics/asterix/builders/UnorderedListBuilder.java
index d4fd029..90fb2b5 100644
--- a/asterix-om/src/main/java/edu/uci/ics/asterix/builders/UnorderedListBuilder.java
+++ b/asterix-om/src/main/java/edu/uci/ics/asterix/builders/UnorderedListBuilder.java
@@ -61,7 +61,7 @@
     public void addItem(IValueReference item) throws HyracksDataException {
         if (!fixedSize)
             this.offsets.add((short) outputStream.size());
-        if (itemTypeTag == ATypeTag.ANY || item.getByteArray()[0] == serNullTypeTag) {
+        if (itemTypeTag == ATypeTag.ANY || (itemTypeTag == ATypeTag.NULL && item.getByteArray()[0] == serNullTypeTag)) {
             this.numberOfItems++;
             this.outputStream.write(item.getByteArray(), item.getStartOffset(), item.getLength());
         } else if (item.getByteArray()[0] != serNullTypeTag) {