diff --git a/doc/OpenSTA.odt b/doc/OpenSTA.odt
index 44c18ac5..5c2ba015 100644
Binary files a/doc/OpenSTA.odt and b/doc/OpenSTA.odt differ
diff --git a/doc/OpenSTA.pdf b/doc/OpenSTA.pdf
index b09c49c2..b2355614 100644
Binary files a/doc/OpenSTA.pdf and b/doc/OpenSTA.pdf differ
diff --git a/include/sta/Sta.hh b/include/sta/Sta.hh
index be5433d8..ebd0a1d8 100644
--- a/include/sta/Sta.hh
+++ b/include/sta/Sta.hh
@@ -914,8 +914,10 @@ public:
   void reportClkSkew(ConstClockSeq clks,
 		     const Corner *corner,
 		     const SetupHold *setup_hold,
+                     bool include_internal_latency,
 		     int digits);
-  float findWorstClkSkew(const SetupHold *setup_hold);
+  float findWorstClkSkew(const SetupHold *setup_hold,
+                         bool include_internal_latency);
 
   void reportClkLatency(ConstClockSeq clks,
                         const Corner *corner,
diff --git a/search/ClkSkew.cc b/search/ClkSkew.cc
index 2f52d0c0..1e47247e 100644
--- a/search/ClkSkew.cc
+++ b/search/ClkSkew.cc
@@ -47,6 +47,7 @@ public:
   ClkSkew();
   ClkSkew(PathVertex *src_path,
 	  PathVertex *tgt_path,
+          bool include_internal_latency,
 	  StaState *sta);
   ClkSkew(const ClkSkew &clk_skew);
   void operator=(const ClkSkew &clk_skew);
@@ -54,8 +55,8 @@ public:
   PathVertex *tgtPath() { return &tgt_path_; }
   float srcLatency(StaState *sta);
   float tgtLatency(StaState *sta);
-  float srcClkTreeDelay(StaState *sta);
-  float tgtClkTreeDelay(StaState *sta);
+  float srcInternalClkLatency(StaState *sta);
+  float tgtInternalClkLatency(StaState *sta);
   Crpr crpr(StaState *sta);
   float uncertainty(StaState *sta);
   float skew() const { return skew_; }
@@ -66,6 +67,7 @@ private:
 
   PathVertex src_path_;
   PathVertex tgt_path_;
+  bool include_internal_latency_;
   float skew_;
 };
 
@@ -76,10 +78,12 @@ ClkSkew::ClkSkew() :
 
 ClkSkew::ClkSkew(PathVertex *src_path,
 		 PathVertex *tgt_path,
-		 StaState *sta)
+                 bool include_internal_latency,
+		 StaState *sta) :
+  src_path_(src_path),
+  tgt_path_(tgt_path),
+  include_internal_latency_(include_internal_latency)
 {
-  src_path_ = src_path;
-  tgt_path_ = tgt_path;
   skew_ = srcLatency(sta)
     - tgtLatency(sta)
     - delayAsFloat(crpr(sta))
@@ -90,6 +94,7 @@ ClkSkew::ClkSkew(const ClkSkew &clk_skew)
 {
   src_path_ = clk_skew.src_path_;
   tgt_path_ = clk_skew.tgt_path_;
+  include_internal_latency_ = clk_skew.include_internal_latency_;
   skew_ = clk_skew.skew_;
 }
 
@@ -98,6 +103,7 @@ ClkSkew::operator=(const ClkSkew &clk_skew)
 {
   src_path_ = clk_skew.src_path_;
   tgt_path_ = clk_skew.tgt_path_;
+  include_internal_latency_ = clk_skew.include_internal_latency_;
   skew_ = clk_skew.skew_;
 }
 
@@ -110,7 +116,7 @@ ClkSkew::srcLatency(StaState *sta)
 }
 
 float
-ClkSkew::srcClkTreeDelay(StaState *sta)
+ClkSkew::srcInternalClkLatency(StaState *sta)
 {
   return clkTreeDelay(src_path_, sta);
 }
@@ -124,7 +130,7 @@ ClkSkew::tgtLatency(StaState *sta)
 }
 
 float
-ClkSkew::tgtClkTreeDelay(StaState *sta)
+ClkSkew::tgtInternalClkLatency(StaState *sta)
 {
   return clkTreeDelay(tgt_path_, sta);
 }
@@ -133,13 +139,17 @@ float
 ClkSkew::clkTreeDelay(PathVertex &clk_path,
                       StaState *sta)
 {
-  const Vertex *vertex = clk_path.vertex(sta);
-  const Pin *pin = vertex->pin();
-  const LibertyPort *port = sta->network()->libertyPort(pin);
-  const MinMax *min_max = clk_path.minMax(sta);
-  const RiseFall *rf = clk_path.transition(sta);
-  float slew = delayAsFloat(clk_path.slew(sta));
-  return port->clkTreeDelay(slew, rf, min_max);
+  if (include_internal_latency_) {
+    const Vertex *vertex = clk_path.vertex(sta);
+    const Pin *pin = vertex->pin();
+    const LibertyPort *port = sta->network()->libertyPort(pin);
+    const MinMax *min_max = clk_path.minMax(sta);
+    const RiseFall *rf = clk_path.transition(sta);
+    float slew = delayAsFloat(clk_path.slew(sta));
+    return port->clkTreeDelay(slew, rf, min_max);
+  }
+  else
+    return 0.0;
 }
 
 Crpr
@@ -171,9 +181,11 @@ void
 ClkSkews::reportClkSkew(ConstClockSeq clks,
 			const Corner *corner,
 			const SetupHold *setup_hold,
+                        bool include_internal_latency,
 			int digits)
 {
-  ClkSkewMap skews = findClkSkew(clks, corner, setup_hold);
+  ClkSkewMap skews = findClkSkew(clks, corner, setup_hold,
+                                 include_internal_latency);
 
   // Sort the clocks to report in a stable order.
   ConstClockSeq sorted_clks;
@@ -201,29 +213,29 @@ ClkSkews::reportClkSkew(ClkSkew &clk_skew,
   PathVertex *tgt_path = clk_skew.tgtPath();
   float src_latency = clk_skew.srcLatency(this);
   float tgt_latency = clk_skew.tgtLatency(this);
-  float src_clk_tree_delay = clk_skew.srcClkTreeDelay(this);
-  float tgt_clk_tree_delay = clk_skew.tgtClkTreeDelay(this);
+  float src_internal_clk_latency = clk_skew.srcInternalClkLatency(this);
+  float tgt_internal_clk_latency = clk_skew.tgtInternalClkLatency(this);
   float uncertainty = clk_skew.uncertainty(this);
 
-  if (src_clk_tree_delay != 0.0)
-    src_latency -= src_clk_tree_delay;
+  if (src_internal_clk_latency != 0.0)
+    src_latency -= src_internal_clk_latency;
   report_->reportLine("%7s source latency %s %s",
                       time_unit->asString(src_latency, digits),
                       sdc_network_->pathName(src_path->pin(this)),
                       src_path->transition(this)->asString());
-  if (src_clk_tree_delay != 0.0)
+  if (src_internal_clk_latency != 0.0)
     report_->reportLine("%7s source internal clock delay",
-                        time_unit->asString(src_clk_tree_delay, digits));
+                        time_unit->asString(src_internal_clk_latency, digits));
 
-  if (tgt_clk_tree_delay != 0.0)
-    tgt_latency -= tgt_clk_tree_delay;
+  if (tgt_internal_clk_latency != 0.0)
+    tgt_latency -= tgt_internal_clk_latency;
   report_->reportLine("%7s target latency %s %s",
                       time_unit->asString(-tgt_latency, digits),
                       sdc_network_->pathName(tgt_path->pin(this)),
                       tgt_path->transition(this)->asString());
-  if (tgt_clk_tree_delay != 0.0)
+  if (tgt_internal_clk_latency != 0.0)
     report_->reportLine("%7s target internal clock delay",
-                        time_unit->asString(-tgt_clk_tree_delay, digits));
+                        time_unit->asString(-tgt_internal_clk_latency, digits));
   if (uncertainty != 0.0)
     report_->reportLine("%7s clock uncertainty",
                         time_unit->asString(uncertainty, digits));
@@ -238,12 +250,13 @@ ClkSkews::reportClkSkew(ClkSkew &clk_skew,
 
 float
 ClkSkews::findWorstClkSkew(const Corner *corner,
-                           const SetupHold *setup_hold)
+                           const SetupHold *setup_hold,
+                           bool include_internal_latency)
 {
   ConstClockSeq clks;
   for (const Clock *clk : *sdc_->clocks())
     clks.push_back(clk);
-  ClkSkewMap skews = findClkSkew(clks, corner, setup_hold);
+  ClkSkewMap skews = findClkSkew(clks, corner, setup_hold, include_internal_latency);
   float worst_skew = 0.0;
   for (auto clk_skew_itr : skews) {
     ClkSkew &clk_skew = clk_skew_itr.second;
@@ -257,7 +270,8 @@ ClkSkews::findWorstClkSkew(const Corner *corner,
 ClkSkewMap
 ClkSkews::findClkSkew(ConstClockSeq &clks,
 		      const Corner *corner,
-		      const SetupHold *setup_hold)
+		      const SetupHold *setup_hold,
+                      bool include_internal_latency)
 {	      
   ClkSkewMap skews;
 
@@ -277,7 +291,8 @@ ClkSkews::findClkSkew(ConstClockSeq &clks,
 	    ? rf->asRiseFallBoth()
 	    : RiseFallBoth::riseFall();
 	  findClkSkewFrom(src_vertex, q_vertex, src_rf, clk_set,
-			  corner, setup_hold, skews);
+			  corner, setup_hold, include_internal_latency,
+                          skews);
 	}
       }
     }
@@ -306,6 +321,7 @@ ClkSkews::findClkSkewFrom(Vertex *src_vertex,
                           ConstClockSet &clk_set,
 			  const Corner *corner,
 			  const SetupHold *setup_hold,
+                          bool include_internal_latency,
 			  ClkSkewMap &skews)
 {
   VertexSet endpoints = findFanout(q_vertex);
@@ -325,7 +341,8 @@ ClkSkews::findClkSkewFrom(Vertex *src_vertex,
 	  ? tgt_rf1->asRiseFallBoth()
 	  : RiseFallBoth::riseFall();
 	findClkSkew(src_vertex, src_rf, tgt_vertex, tgt_rf,
-		    clk_set, corner, setup_hold, skews);
+		    clk_set, corner, setup_hold,
+                    include_internal_latency, skews);
       }
     }
   }
@@ -339,6 +356,7 @@ ClkSkews::findClkSkew(Vertex *src_vertex,
                       ConstClockSet &clk_set,
 		      const Corner *corner,
 		      const SetupHold *setup_hold,
+                      bool include_internal_latency,
                       ClkSkewMap &skews)
 {
   Unit *time_unit = units_->timeUnit();
@@ -362,7 +380,7 @@ ClkSkews::findClkSkew(Vertex *src_vertex,
 	      && tgt_rf->matches(tgt_path->transition(this))
 	      && tgt_path->minMax(this) == tgt_min_max
 	      && tgt_path->pathAnalysisPt(this)->corner() == src_corner) {
-	    ClkSkew probe(src_path, tgt_path, this);
+	    ClkSkew probe(src_path, tgt_path, include_internal_latency, this);
 	    ClkSkew &clk_skew = skews[src_clk];
 	    debugPrint(debug_, "clk_skew", 2,
                        "%s %s %s -> %s %s %s crpr = %s skew = %s",
diff --git a/search/ClkSkew.hh b/search/ClkSkew.hh
index ca2491b3..36f3b6eb 100644
--- a/search/ClkSkew.hh
+++ b/search/ClkSkew.hh
@@ -39,15 +39,18 @@ public:
   void reportClkSkew(ConstClockSeq clks,
 		     const Corner *corner,
 		     const SetupHold *setup_hold,
+                     bool include_internal_latency,
 		     int digits);
   // Find worst clock skew between src/target registers.
   float findWorstClkSkew(const Corner *corner,
-                         const SetupHold *setup_hold);
+                         const SetupHold *setup_hold,
+                         bool include_internal_latency);
   
 protected:
   ClkSkewMap findClkSkew(ConstClockSeq &clks,
                          const Corner *corner,
-                         const SetupHold *setup_hold);
+                         const SetupHold *setup_hold,
+                         bool include_internal_latency);
   bool hasClkPaths(Vertex *vertex,
 		   ConstClockSet &clks);
   void findClkSkewFrom(Vertex *src_vertex,
@@ -56,6 +59,7 @@ protected:
 		       ConstClockSet &clk_set,
 		       const Corner *corner,
 		       const SetupHold *setup_hold,
+                       bool include_internal_latency,
 		       ClkSkewMap &skews);
   void findClkSkew(Vertex *src_vertex,
 		   const RiseFallBoth *src_rf,
@@ -64,6 +68,7 @@ protected:
                    ConstClockSet &clk_set,
 		   const Corner *corner,
 		   const SetupHold *setup_hold,
+                   bool include_internal_latency,
 		   ClkSkewMap &skews);
   VertexSet findFanout(Vertex *from);
   void reportClkSkew(ClkSkew &clk_skew,
diff --git a/search/Sta.cc b/search/Sta.cc
index fd001418..546475a3 100644
--- a/search/Sta.cc
+++ b/search/Sta.cc
@@ -2604,17 +2604,21 @@ void
 Sta::reportClkSkew(ConstClockSeq clks,
 		   const Corner *corner,
 		   const SetupHold *setup_hold,
+                   bool include_internal_latency,
 		   int digits)
 {
   clkSkewPreamble();
-  clk_skews_->reportClkSkew(clks, corner, setup_hold, digits);
+  clk_skews_->reportClkSkew(clks, corner, setup_hold,
+                            include_internal_latency, digits);
 }
 
 float
-Sta::findWorstClkSkew(const SetupHold *setup_hold)
+Sta::findWorstClkSkew(const SetupHold *setup_hold,
+                      bool include_internal_latency)
 {
   clkSkewPreamble();
-  return clk_skews_->findWorstClkSkew(cmd_corner_, setup_hold);
+  return clk_skews_->findWorstClkSkew(cmd_corner_, setup_hold,
+                                      include_internal_latency);
 }
 
 void
diff --git a/tcl/Search.tcl b/tcl/Search.tcl
index 9d4100c4..f93085e6 100644
--- a/tcl/Search.tcl
+++ b/tcl/Search.tcl
@@ -311,15 +311,17 @@ proc delays_are_inf { delays } {
 ################################################################
 
 define_cmd_args "report_clock_skew" {[-setup|-hold]\
-					   [-clock clocks]\
-					   [-corner corner]\
-					   [-digits digits]}
+                                       [-clock clocks]\
+                                       [-corner corner]\
+                                       [-include_internal_latency]
+                                       [-digits digits]}
 
 proc_redirect report_clock_skew {
   global sta_report_default_digits
 
   parse_key_args "report_clock_skew" args \
-    keys {-clock -corner -digits} flags {-setup -hold}
+    keys {-clock -corner -digits} \
+    flags {-setup -hold -include_internal_latency}
   check_argc_eq0 "report_clock_skew" $args
 
   if { [info exists flags(-setup)] && [info exists flags(-hold)] } {
@@ -338,6 +340,7 @@ proc_redirect report_clock_skew {
     set clks [all_clocks]
   }
   set corner [parse_corner_or_all keys]
+  set include_internal_latency [info exists flags(-include_internal_latency)]
   if [info exists keys(-digits)] {
     set digits $keys(-digits)
     check_positive_integer "-digits" $digits
@@ -345,7 +348,7 @@ proc_redirect report_clock_skew {
     set digits $sta_report_default_digits
   }
   if { $clks != {} } {
-    report_clk_skew $clks $corner $setup_hold $digits
+    report_clk_skew $clks $corner $setup_hold $include_internal_latency $digits
   }
 }
 
@@ -995,10 +998,12 @@ proc worst_slack1 { cmd args1 } {
 
 ################################################################
 
-define_hidden_cmd_args "worst_clock_skew" {[-setup]|[-hold]}
+define_hidden_cmd_args "worst_clock_skew" \
+  {[-setup]|[-hold][-include_internal_latency]}
 
 proc worst_clock_skew { args } {
-  parse_key_args "worst_clock_skew" args keys {} flags {-setup -hold}
+  parse_key_args "worst_clock_skew" args keys {} \
+    flags {-setup -hold -include_internal_latency}
   check_argc_eq0 "worst_clock_skew" $args
   if { ([info exists flags(-setup)] && [info exists flags(-hold)]) \
          || (![info exists flags(-setup)] && ![info exists flags(-hold)]) } {
@@ -1008,7 +1013,8 @@ proc worst_clock_skew { args } {
   } elseif { [info exists flags(-hold)] } {
     set setup_hold "hold"
   }
-  return [time_sta_ui [worst_clk_skew_cmd $setup_hold]]
+  set include_internal_latency [info exists flags(-include_internal_latency)]
+ return [time_sta_ui [worst_clk_skew_cmd $setup_hold $include_internal_latency]]
 }
 
 ################################################################
diff --git a/tcl/StaTcl.i b/tcl/StaTcl.i
index 1d45e6e1..6977cd87 100644
--- a/tcl/StaTcl.i
+++ b/tcl/StaTcl.i
@@ -3034,14 +3034,18 @@ report_path_cmd(PathRef *path)
   Sta::sta()->reportPath(path);
 }
 
+////////////////////////////////////////////////////////////////
+
 void
 report_clk_skew(ConstClockSeq clks,
 		const Corner *corner,
 		const SetupHold *setup_hold,
+                bool include_internal_latency,
 		int digits)
 {
   cmdLinkedNetwork();
-  Sta::sta()->reportClkSkew(clks, corner, setup_hold, digits);
+  Sta::sta()->reportClkSkew(clks, corner, setup_hold,
+                            include_internal_latency, digits);
 }
 
 void
@@ -3054,12 +3058,15 @@ report_clk_latency(ConstClockSeq clks,
 }
 
 float
-worst_clk_skew_cmd(const SetupHold *setup_hold)
+worst_clk_skew_cmd(const SetupHold *setup_hold,
+                   bool include_internal_latency)
 {
   cmdLinkedNetwork();
-  return Sta::sta()->findWorstClkSkew(setup_hold);
+  return Sta::sta()->findWorstClkSkew(setup_hold, include_internal_latency);
 }
 
+////////////////////////////////////////////////////////////////
+
 PinSet
 startpoints()
 {