diff --git a/inception/inception-recommendation/src/main/java/de/tudarmstadt/ukp/inception/recommendation/util/OverlapIterator.java b/inception/inception-recommendation/src/main/java/de/tudarmstadt/ukp/inception/recommendation/util/OverlapIterator.java
index 4f685518e89..efc738f4982 100644
--- a/inception/inception-recommendation/src/main/java/de/tudarmstadt/ukp/inception/recommendation/util/OverlapIterator.java
+++ b/inception/inception-recommendation/src/main/java/de/tudarmstadt/ukp/inception/recommendation/util/OverlapIterator.java
@@ -91,7 +91,7 @@ else if (ib.hasNext()) {
             // Step to the next B from the source list
             LOG.trace("Stepping B from source Bs");
             b = ib.next();
-            if (b.getBegin() > a.getEnd()) {
+            if (a != null && b.getBegin() > a.getEnd()) {
                 // All remaining b's are beyond the end of the a's and won't overlap
                 a = null;
             }