diff --git a/gtsam/hybrid/HybridBayesNet.cpp b/gtsam/hybrid/HybridBayesNet.cpp
index 5353fe2e0..dbf94ea59 100644
--- a/gtsam/hybrid/HybridBayesNet.cpp
+++ b/gtsam/hybrid/HybridBayesNet.cpp
@@ -65,6 +65,7 @@ HybridBayesNet HybridBayesNet::prune(
   }
 
   HybridBayesNet result;
+  result.reserve(size());
 
   // Go through all the Gaussian conditionals, restrict them according to
   // fixed values, and then prune further.
@@ -84,9 +85,9 @@ HybridBayesNet HybridBayesNet::prune(
       }
       // Type-erase and add to the pruned Bayes Net fragment.
       result.push_back(prunedHybridGaussianConditional);
-    } else if (auto gc = conditional->asGaussian()) {
-      // Add the non-HybridGaussianConditional conditional
-      result.push_back(gc);
+    } else if (conditional->isContinuous()) {
+      // Add the non-Hybrid GaussianConditional conditional
+      result.push_back(conditional);
     } else
       throw std::runtime_error(
           "HybrdiBayesNet::prune: Unknown HybridConditional type.");
diff --git a/gtsam/hybrid/HybridFactor.cpp b/gtsam/hybrid/HybridFactor.cpp
index 3338951bf..627da4fe6 100644
--- a/gtsam/hybrid/HybridFactor.cpp
+++ b/gtsam/hybrid/HybridFactor.cpp
@@ -23,6 +23,7 @@ namespace gtsam {
 KeyVector CollectKeys(const KeyVector &continuousKeys,
                       const DiscreteKeys &discreteKeys) {
   KeyVector allKeys;
+  allKeys.reserve(continuousKeys.size() + discreteKeys.size());
   std::copy(continuousKeys.begin(), continuousKeys.end(),
             std::back_inserter(allKeys));
   std::transform(discreteKeys.begin(), discreteKeys.end(),
@@ -34,6 +35,7 @@ KeyVector CollectKeys(const KeyVector &continuousKeys,
 /* ************************************************************************ */
 KeyVector CollectKeys(const KeyVector &keys1, const KeyVector &keys2) {
   KeyVector allKeys;
+  allKeys.reserve(keys1.size() + keys2.size());
   std::copy(keys1.begin(), keys1.end(), std::back_inserter(allKeys));
   std::copy(keys2.begin(), keys2.end(), std::back_inserter(allKeys));
   return allKeys;