diff --git a/lib/net/imap/sequence_set.rb b/lib/net/imap/sequence_set.rb
index 29c59e800..ecd113e9a 100644
--- a/lib/net/imap/sequence_set.rb
+++ b/lib/net/imap/sequence_set.rb
@@ -2435,7 +2435,7 @@ def slice_range(range)
         if (first * last).positive? && last < first
           remain_frozen_empty
         elsif (min = sorted_set_num_at(first))
-          max = sorted_set_num_at(last) || STAR_INT
+          max = sorted_set_num_at(last) || (last.negative? ? 0 : STAR_INT)
           if    min <= max then intersection export_minmax_entry [min, max]
           else                  remain_frozen_empty
           end
diff --git a/test/net/imap/test_sequence_set.rb b/test/net/imap/test_sequence_set.rb
index bd3801076..b1b9acb35 100644
--- a/test/net/imap/test_sequence_set.rb
+++ b/test/net/imap/test_sequence_set.rb
@@ -489,13 +489,6 @@ def obj.to_sequence_set; 192_168.001_255 end
 
   def pend_slice_bug(what, &) = pend("#slice bug: #{what}", &)
 
-  def pend_slice_lomax(set, start, actual)
-    pend_slice_bug "return empty when max < -cardinality" do
-      assert_same empty, actual
-    end
-    assert_equal set[start..], actual
-  end
-
   def pend_slice_nil(actual)
     pend_slice_bug "return nil for invalid slice start index" do
       assert_nil actual
@@ -613,11 +606,11 @@ def pend_slice_zero_len(&)
 
   test "#[range] -> empty, for empty positive..negative range with valid start" do
     set = SequenceSet[1..200]
-    pend_slice_lomax set, 0,            set[  0.. -201]  # i.e:   0.. before start
-    pend_slice_lomax set, 0,            set[  0...-200]  # i.e:   0...  0
+    assert_same SequenceSet.empty, set[  0.. -201]  # i.e:   0.. before start
+    assert_same SequenceSet.empty, set[  0...-200]  # i.e:   0...  0
     assert_same SequenceSet.empty, set[  1.. -200]  # i.e:   1..   0
-    pend_slice_lomax set, 100,          set[100.. -201]  # i.e: 100.. before first
-    pend_slice_lomax set, 100,          set[100...-200]  # i.e: 100...  0
+    assert_same SequenceSet.empty, set[100.. -201]  # i.e: 100.. before first
+    assert_same SequenceSet.empty, set[100...-200]  # i.e: 100...  0
     assert_same SequenceSet.empty, set[100...-100]  # i.e: 100...100
     assert_same SequenceSet.empty, set[100.. -101]  # i.e: 100..  99
     assert_same SequenceSet.empty, set[199...  -1]  # i.e: 199...199