diff --git a/org.sat4j.pb/src/main/java/org/sat4j/pb/tools/PreprocCardConstrLearningSolver.java b/org.sat4j.pb/src/main/java/org/sat4j/pb/tools/PreprocCardConstrLearningSolver.java
index 2e2c3f1ea1221d3708a252f5c141c485dbd0efa6..6df8bc4da1da804e33efdf32870b56f1efe6234f 100644
--- a/org.sat4j.pb/src/main/java/org/sat4j/pb/tools/PreprocCardConstrLearningSolver.java
+++ b/org.sat4j.pb/src/main/java/org/sat4j/pb/tools/PreprocCardConstrLearningSolver.java
@@ -132,8 +132,9 @@ public class PreprocCardConstrLearningSolver<S extends IPBSolver>
             newMinBound = newMinBound.add(weights.get(i));
         }
         if (this.objMinBound == null
-                || this.objMinBound.compareTo(newMinBound) == -1)
+                || this.objMinBound.compareTo(newMinBound) < 0) {
             this.objMinBound = newMinBound;
+        }
     }
 
     private void rissPreprocessing() {