SPG has sent out emails with an offer for 2,500 Starpoints for adding an authorized user and spending $1,000 on the new card within the first three months.
Add authorized user here. The offer does not show up in this page, so it’s not 100% guaranteed that it will work. The offer mentions that it is not transferable in the fine print.
Also keep in mind that you need to enter SSN for the authorized user and it will count towards Chase’s 5/24 rule.