There was an interesting blog I read a few days ago by someone attending a loyalty conference. One the speakers was from MR who said that the overlap between participants in the programs was 11%. Marriott originally thought it would be 16%. If that is indeed true, the number of participants reaching LT status when the programs are combined may not be that great.

After reading the article, I did wonder how they calculated the overlap-- was it by the number of linked accounts or by cross-listing account data (I've not linked my accounts yet). I also wonder how many MR participants (like me) are actively churning the SPG AMEX cards this year.

Here is the article if you're interested:

http://blog.wandr.me/2017/02/reducin...wards-program/