diff --git a/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFBMuMuFex.cxx b/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFBMuMuFex.cxx
index 92114749a94e8a5180e3e13ebbf7387d2293d457..f0190d1a12f4f73a30345f86837f0de8c9566625 100644
--- a/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFBMuMuFex.cxx
+++ b/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFBMuMuFex.cxx
@@ -1,7 +1,7 @@
 // -*- C++ -*-
 
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 /**************************************************************************
@@ -331,7 +331,7 @@ HLT::ErrorCode TrigEFBMuMuFex::acceptInputs(HLT::TEConstVec& inputTE, bool& pass
     // print debug info
     if(msgLvl() <= MSG::DEBUG) {
         int ic(0);
-        for ( const auto muelv : vec_elv_muons) {
+        for ( const auto& muelv : vec_elv_muons) {
             // loop over the vector of muon containers
             msg() << MSG::DEBUG << "MuonContainer, Got MuonEF " << ic << " Feature, size = " << muelv.size() << endmsg;
             int i(0);
@@ -360,7 +360,7 @@ HLT::ErrorCode TrigEFBMuMuFex::acceptInputs(HLT::TEConstVec& inputTE, bool& pass
             ++ic;
         } // for muons
         ic =0;
-        for ( const auto tpelv : vec_elv_tps) {
+        for ( const auto& tpelv : vec_elv_tps) {
             msg() << MSG::DEBUG <<  "SATrackParticleContainer, Got MUSA " << ic << " Feature, size = " << tpelv.size() << endmsg;
             int i(0);
             for ( const auto tpel: tpelv) {
diff --git a/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFMultiMuFex.cxx b/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFMultiMuFex.cxx
index b2697df0c15f4a8440a55650a46a2c2c83ccda6a..4cc889324b06e87bffc999a5db30467673dad2ac 100644
--- a/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFMultiMuFex.cxx
+++ b/Trigger/TrigHypothesis/TrigBphysHypo/src/TrigEFMultiMuFex.cxx
@@ -1,7 +1,7 @@
 // -*- C++ -*-
 
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 /**************************************************************************
@@ -256,7 +256,7 @@ void TrigEFMultiMuFex::processTriMuon(HLT::TEConstVec& inputTE, xAOD::TrigBphysC
 
     if(msgLvl() <= MSG::DEBUG) {
         int ic(0);
-        for ( const auto muelv : vec_elv_muons) {
+        for ( const auto& muelv : vec_elv_muons) {
             // loop over the vector of muon containers
             msg() << MSG::DEBUG << "MuonContainer, Got MuonEF " << ic << " Feature, size = " << muelv.size() << endmsg;
             int i(0);
@@ -289,7 +289,7 @@ void TrigEFMultiMuFex::processTriMuon(HLT::TEConstVec& inputTE, xAOD::TrigBphysC
     
     std::vector<const xAOD::Muon*> uniqueMuons;
     // add all the unique muons into a single container
-    for ( const auto muelv : vec_elv_muons) {
+    for ( const auto& muelv : vec_elv_muons) {
         for ( const auto muel : muelv ) {
             m_bphysHelperTool->addUnique( *muel, uniqueMuons, 0.005,0.005,10,xAOD::Muon::InnerDetectorTrackParticle);
         } // loop over muonEL in each roi
diff --git a/Trigger/TrigHypothesis/TrigHLTJetHypo/src/MultijetFlowNetworkBuilder.cxx b/Trigger/TrigHypothesis/TrigHLTJetHypo/src/MultijetFlowNetworkBuilder.cxx
index 0d286b048b55140f3643d4507f179338a6eaf8c3..253997a38a8ec100f92a63875138c501dbad3482 100644
--- a/Trigger/TrigHypothesis/TrigHLTJetHypo/src/MultijetFlowNetworkBuilder.cxx
+++ b/Trigger/TrigHypothesis/TrigHLTJetHypo/src/MultijetFlowNetworkBuilder.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #include "./MultijetFlowNetworkBuilder.h"
@@ -72,7 +72,7 @@ MultijetFlowNetworkBuilder::make_flowEdges(const HypoJetGroupCIter& groups_b,
   //obtain a list of job groups without duplicits:
 
   std::set<int> u_jgroups;
-  for(const auto jgis: *matches){u_jgroups.insert(jgis.begin(), jgis.end());}
+  for(const auto& jgis: *matches){u_jgroups.insert(jgis.begin(), jgis.end());}
 
   // a jet may appear inmore than one matched job group. Ensure it recieves
   // one node number.
diff --git a/Trigger/TrigMonitoring/TrigBjetMonitoring/src/HLTBjetMonTool.cxx b/Trigger/TrigMonitoring/TrigBjetMonitoring/src/HLTBjetMonTool.cxx
index bcef5e4e6041a97b7a833633b120042a9fdac950..52d4c28860d8a108b9ddc189644892995403afac 100755
--- a/Trigger/TrigMonitoring/TrigBjetMonitoring/src/HLTBjetMonTool.cxx
+++ b/Trigger/TrigMonitoring/TrigBjetMonitoring/src/HLTBjetMonTool.cxx
@@ -1075,7 +1075,7 @@ StatusCode HLTBjetMonTool::book(){
 	std::vector< TrigCompositeUtils::LinkInfo<xAOD::JetContainer> > onlinejets = m_trigDec->features<xAOD::JetContainer>(trigItem, TrigDefs::Physics, m_onlineBjetContainerKey); // TM 240320
 	int ijet = 0;
 	int itrack = 0;
-	for(const auto jetLinkInfo : onlinejets) {
+	for(const auto& jetLinkInfo : onlinejets) {
 	  // jetPt
 	  const xAOD::Jet* jet = *(jetLinkInfo.link);
 	  ATH_MSG_DEBUG("                 -   pt/eta/phi: " << (jet->pt())*1.e-3 << " / " << jet->eta() << " / " << jet->phi());
diff --git a/Trigger/TrigMonitoring/TrigBjetMonitoring/src/TrigBjetMonitorAlgorithm.cxx b/Trigger/TrigMonitoring/TrigBjetMonitoring/src/TrigBjetMonitorAlgorithm.cxx
index 503e71ac1b32747c319d37732f41e02aa974ae25..c714e534bcd70b7318be4a0ef16993c80e5d8571 100644
--- a/Trigger/TrigMonitoring/TrigBjetMonitoring/src/TrigBjetMonitorAlgorithm.cxx
+++ b/Trigger/TrigMonitoring/TrigBjetMonitoring/src/TrigBjetMonitorAlgorithm.cxx
@@ -348,7 +348,7 @@ StatusCode TrigBjetMonitorAlgorithm::fillHistograms( const EventContext& ctx ) c
 	  auto nJet = Monitored::Scalar<int>(nJetH,0.0);
 	  nJet = onlinejets.size();
 	  fill("TrigBjetMonitor",nJet);
-	  for(const auto jetLinkInfo : onlinejets) {
+	  for(const auto& jetLinkInfo : onlinejets) {
 	    // jetPt
 	    const xAOD::Jet* jet = *(jetLinkInfo.link);
 	    std::string NameH = "jetPt_"+trigName;