diff --git a/sys/dev/sound/pcm/mixer.c b/sys/dev/sound/pcm/mixer.c
index 8d96486c862..3ddee24417c 100644
--- a/sys/dev/sound/pcm/mixer.c
+++ b/sys/dev/sound/pcm/mixer.c
@@ -5,6 +5,10 @@
  * Portions Copyright (c) Ryan Beasley <ryan.beasley@gmail.com> - GSoC 2006
  * Copyright (c) 1999 Cameron Grant <cg@FreeBSD.org>
  * All rights reserved.
+ * Copyright (c) 2026 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Christos Margiolis
+ * <christos@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
diff --git a/sys/dev/sound/pcm/mixer.h b/sys/dev/sound/pcm/mixer.h
index 34f0514c627..6f764307cfc 100644
--- a/sys/dev/sound/pcm/mixer.h
+++ b/sys/dev/sound/pcm/mixer.h
@@ -4,6 +4,10 @@
  * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
  * Copyright (c) 1999 Cameron Grant <cg@FreeBSD.org>
  * All rights reserved.
+ * Copyright (c) 2026 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Christos Margiolis
+ * <christos@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions