User Group Membership

HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy\GroupMembership contains the groups a user belongs to

Group SIDGroup Name
S-1-5-32-544Local Admins
S-1-5-21-domain-500Administrator
S-1-5-21-domain-512Domain Admins
S-1-5-21-domain-518Schema Admins
S-1-5-21-domain-519Enterprise Admins
S-1-5-21-domain-520Group Policy Admins