diff --git a/Misc/NEWS b/Misc/NEWS
index f1aec99..822d1c9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,13 @@
 Core and Builtins
 -----------------
 
+- Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to 
+  match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__
+  mechanism. In the process, fix a bug where isinstance() and issubclass(),
+  when given a tuple of classes as second argument, were looking up
+  __instancecheck__ / __subclasscheck__ on the tuple rather than on each
+  type object.
+
 - Fix crashes on memory allocation failure found with failmalloc.
 
 - Fix memory leaks found with valgrind and update suppressions file.