diff --git a/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/MatrixNtupleBranch.h b/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/MatrixNtupleBranch.h
index b4c101785aae06669ec7e2d328d45a58a469cfd5..3d9863a983d7357b50fed712fb72f53cc6d8afe2 100644
--- a/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/MatrixNtupleBranch.h
+++ b/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/MatrixNtupleBranch.h
@@ -31,7 +31,6 @@ namespace Trk {
   */
 
   struct MatrixNtupleBranch {
-    MatrixNtupleBranch() : m_nrows(-1),m_ncols(-1) {}
 
     /** initialize class for writing */
     bool initForWrite(TTree& tree, const std::string& varname, int ncol, int nrow, const std::string& prefix = ""  );
@@ -48,9 +47,9 @@ namespace Trk {
     /** data */
     static const int COLMAX = 10;
     static const int ROWMAX = 10;
-    int m_nrows;
-    int m_ncols;
-    float  m_matrix[COLMAX][ROWMAX]; 
+    int m_nrows{-1};
+    int m_ncols{-1};
+    float  m_matrix[COLMAX][ROWMAX]{}; 
   };   
 
 }
diff --git a/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/VectorNtupleBranch.h b/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/VectorNtupleBranch.h
index bd8ac407bb83fd884122f55674cf6a43e2c9c738..e320ebd20f1f9773100bd9bb84044ea8ac26e108 100644
--- a/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/VectorNtupleBranch.h
+++ b/Tracking/TrkUtilityPackages/TrkValidationUtils/TrkValidationUtils/VectorNtupleBranch.h
@@ -32,7 +32,6 @@ namespace Trk {
      }
   */
   struct VectorNtupleBranch {
-    VectorNtupleBranch() : m_nrows(-1) {}
 
     /** initialize class for writing */
     bool initForWrite(TTree& tree, const std::string& varname, int nrow, const std::string& prefix = ""  );
@@ -57,8 +56,8 @@ namespace Trk {
 
     /** maximum size of the vector */
     static const int ROWMAX = 10;
-    int m_nrows;
-    float  m_vector[ROWMAX]; 
+    int m_nrows {-1};
+    float  m_vector[ROWMAX]{}; 
   };   
 
 }