diff --git a/pgpy/packet/subpackets/signature.py b/pgpy/packet/subpackets/signature.py
index a68a0bd9..423c9fc3 100644
--- a/pgpy/packet/subpackets/signature.py
+++ b/pgpy/packet/subpackets/signature.py
@@ -52,7 +52,6 @@
            'Policy',
            'KeyFlags',
            'SignersUserID',
-           'SubkeyBindingSignature',
            'ReasonForRevocation',
            'Features',
            'EmbeddedSignature',
@@ -704,11 +703,7 @@ class PreferredKeyServer(URI):
     __typeid__ = 0x18
 
 
-class SubkeyBindingSignature(Signature):
-    __typeid__ = 0x18
-
-
-class PrimaryUserID(SubkeyBindingSignature):
+class PrimaryUserID(Signature):
     __typeid__ = 0x19
 
     @sdproperty