I have points with my American express credit card towards SPG. Should I transfer this points to Marriott before the August surprises?
To accomplish what? Are you afraid they will disappear? If you have a redemption, yes, if you need them for LT points and use yogib's thread, yes... otherwise, does it matter???
Wait - SPG AMEX points, or AMEX membership rewards points? My comment was based on them being SPG points from an SPG AMEX card, not membership rewards points. If they are AMEX membership rewards points, then no, I wouldn't transfer them, unless I needed points for a particular redemption.
The 1 Starpoint = 3 Marriott Rewards Points ratio that is in effect now will remain in effect then. Put the points wherever you need them for redemptions prior to August. If you will keep them through the change, then there really is no point in moving them around.
Are you talking about AmEx Membership Rewards points?
In that case: if you really want to redeem them at Starwood/Marriott, then you should definitely transfer your Rewards Points to your SPG account before August.
In theory, you can still keep your old SPG account until December 31st, given that you don't opt in to merge your accounts in August. But there are still a lot of misty sights in what Marriott has in store for all the loyalty members starting August. As you probably have seen in the list of participating programs to exchange points, only SPG is listed (not Marriott). Therefore I'm recommending transferring before August.
If you're lucky, you can transfer some extra points that you will accumulate in the last part of 2018 until December. I don't see why you can't transfer twice to play it safe.
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