diff --git a/gtsam/hybrid/HybridNonlinearFactorGraph.h b/gtsam/hybrid/HybridNonlinearFactorGraph.h
index ebefb52cb..0cc87d504 100644
--- a/gtsam/hybrid/HybridNonlinearFactorGraph.h
+++ b/gtsam/hybrid/HybridNonlinearFactorGraph.h
@@ -74,7 +74,7 @@ class GTSAM_EXPORT HybridNonlinearFactorGraph : public HybridFactorGraph {
    * @param continuousValues: Dictionary of continuous values.
    * @return HybridGaussianFactorGraph::shared_ptr
    */
-  HybridGaussianFactorGraph::shared_ptr linearize(
+  boost::shared_ptr<HybridGaussianFactorGraph> linearize(
       const Values& continuousValues) const;
   /// @}
 };