So as I think about this some more, the way Starwood will get hit from this is by AMEX buying fewer SPG points from them, as Starwood AMEX credit card usage will almost certainly go down some.

Of course, they have been doing a lot of advertising lately -- and offering that 10,000 point bonus -- so the impact is still probably several months away.

On the other hand, demand for award hotel stays will also go down (again, not immediately, because newcomers will be using up their 10,000 point bonuses). In the scheme of profitability, I doubt the AMEX relationship is THAT important to Starwood. It probably is somewhat important, however. For instance, we know the airline/credit card relationship is VERY important -- witness how the credit card issuers were all major sources of funding in the recent airline bankruptcy cases. I just doubt that SPG has as many credit card holders as the major airlines.