I haven't seen this mentioned anywhere (sorry if it has...), but on my latest Amex Platinum statement I had the following notice:
SPG®
has announced changes to its loyalty program and how its members
will earn Starpoints:
Starpoints will be referred to as points. These points do not refer to
Membership Rewards points.
On August 1, 2018, Starpoint balances in loyalty member accounts will
convert to points at a 1:3 ratio (one Starpoint will convert to three points).
For example, 1,000 Starpoints will become 3,000 points. In general,
the number of points needed to redeem in the loyalty program will have
corresponding changes.
To align with this, we are making changes to the Membership Rewards
Program Terms & Conditions that impact Card Members who are enrolled
in the Membership Rewards program and are eligible for a Membership
Rewards point transfer. Membership Rewards points can now be
transferred at a 1:1 ratio into the Starwood Preferred Guest®
program and
can be transferred in increments of 1,000 points.