As of Jan. 1, Starwood Preferred Guest Starpoints lost some of their value when the point-to-mile conversion rate to United Mileage Plus was changed from 1-to-1 to a 1-to-2.

More than likely, the change was not brought about by Starwood, nor by United (at least not directly). We speculate that BankOne, which provides co-branded Mileage Plus credit cards, put some pressure on United to shut down any conduit to American Express (which provides the Starwood credit card). It’s highly likely that United could not contractually opt out of the SPG program, so instead, it increased the rate that SPG has to pay for miles to a point where SPG could not offer a 1:1 conversion.

In another less-than-popular move, Starwood has raised the “cost” of free stays at its category 5 and category 6 hotels. Five free nights at a category 5 hotel, which used to go for 48,000 points, has been raised 33 percent to 64,000 points. Five nights at a category six hotel, which used to cost 80,000 points, has been raised 20 percent to 100,000 points.

While few dispute Starwood’s right to structure its program as it sees fit, most of the complaints we’ve heard have related to a lack of notice.

Starwood has responded to these comments by offering a special credit to members affected by the changes (see Award Watch).