For the last 3 days I've been trying to transfer some points from Amex membership rewards into my SPG account. And for 3 days when I go and look the next day, the points are back in my MR account with a note that the transfer is cancelled. Neither SPG nor Amex have been of any help in this whatsoever. Today I finally had a glimmer of hope from the Amex MR agent I just spoke with. My accounts were linked before the merger, and the membership number updated automatically. But what we noticed is that for name, the link only has my last name, rather than my full name. It sounds like there may have been a change around this. I'm going to try updating the information and transferring again to see if that does the trick. Hopefully this will be helpful to others who might be in the same boat.

I just wanted to confirm that this was indeed the solution. I de-linked SPG, re-linked it, it added my full name, and the points transferred and showed up in my SPG account instantly.

What a frustrating 4 days trying to get it working.