diff --git a/man7/unix.7 b/man7/unix.7
index 1bc7804f0..d9341a119 100644
--- a/man7/unix.7
+++ b/man7/unix.7
@@ -280,10 +280,16 @@ by specifying
 as the socket family.
 .TP
 .B SO_PASSCRED
-This socket option enables receipt
-of the credentials of the sending process in an
-.BR SCM_CREDENTIALS
-ancillary message.
+This socket option enables receipt of the credentials of
+the sending process in an
+.B SCM_CREDENTIALS ancillary
+message in each subsequently message.
+The returned credentials are those specified by the sender using
+.BR SCM_CREDENTIALS ,
+or a default that includes the sender's PID, real user ID, and real group ID,
+if the sender did not specify
+.B SCM_CREDENTIALS
+ancillary data.
 .IP
 When this option is set and the socket is not yet connected,
 a unique name in the abstract namespace will be generated automatically.