diff --git a/mercurial/merge.py b/mercurial/merge.py
--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -1173,7 +1173,10 @@
 
         # 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)
+        )
         for f, bids in sorted(fbids.items()):
             repo.ui.note(_(b" %s:\n   list of bids:\n") % f)
             for m, l in sorted(bids.items()):
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:
      list of bids:
        remote is newer -> g
@@ -200,7 +200,7 @@
    f1: versions differ -> m
    f2: remote is newer -> g
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1:
      list of bids:
        remote unchanged -> k
@@ -246,7 +246,7 @@
   calculating bids for ancestor 40663881a6dd
   resolving manifests
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1:
      list of bids:
        remote is newer -> g
@@ -281,7 +281,7 @@
    f1: versions differ -> m
    f2: remote unchanged -> k
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    f1:
      list of bids:
        remote is newer -> g
@@ -375,7 +375,7 @@
   calculating bids for ancestor b211bbc6eb3c
   resolving manifests
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    x:
      list of bids:
        versions differ -> m
@@ -465,7 +465,7 @@
    d1/b: other deleted -> r
    d2/b: remote created -> g
   
-  auction for merging merge bids
+  auction for merging merge bids (2 ancestors)
    d1/a:
      list of bids:
        ancestor missing, remote missing -> k