diff --git a/mercurial/merge.py b/mercurial/merge.py
--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -1151,7 +1151,10 @@
 
         # Call for bids
         # Pick the best bid for each file
-        repo.ui.note(_(b'\nauction for merging merge bids\n'))
+        repo.ui.note(
+            _(b'\nauction for merging merge bids (%d ancestors)\n')
+            % len(ancestors)
+        )
         mresult = mergeresult()
         for f, bids in sorted(fbids.items()):
             # bids is a mapping from action method to list af actions
diff --git a/tests/test-merge-criss-cross.t b/tests/test-merge-criss-cross.t
--- a/tests/test-merge-criss-cross.t
+++ b/tests/test-merge-criss-cross.t
@@ -149,7 +149,7 @@
    f1: versions differ -> m
    f2: remote unchanged -> k
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1: picking 'get' action
    f2: picking 'keep' action
   end of auction
@@ -192,7 +192,7 @@
    f1: versions differ -> m
    f2: remote is newer -> g
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1: picking 'keep' action
    f2: picking 'get' action
   end of auction
@@ -230,7 +230,7 @@
   calculating bids for ancestor 40663881a6dd
   resolving manifests
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1: picking 'get' action
    f2: picking 'keep' action
   end of auction
@@ -257,7 +257,7 @@
    f1: versions differ -> m
    f2: remote unchanged -> k
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1: picking 'get' action
    f2: picking 'keep' action
   end of auction
@@ -343,7 +343,7 @@
   calculating bids for ancestor b211bbc6eb3c
   resolving manifests
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    x: multiple bids for merge action:
     versions differ -> m
     versions differ -> m
@@ -430,7 +430,7 @@
    d1/b: other deleted -> r
    d2/b: remote created -> g
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    d1/a: consensus for r
    d1/b: consensus for r
    d2/b: consensus for g