Those are the some of the Chinese cardholders in America. It is not about the BG groups in China. AmEx has little market share in China. There is no such thing of BGs in China, or related to China.

I know exactly what caused the past "waves" of AmEx SDs. I've done that and it may still work with other cards. There are some MS plays that people do not want to share. Some banks caught some of those. Some do not. MS plays come and go. Eventually they all die. Then new ones come along.

Even most of the bloggers do not have much clue. Of all the forum that I read, there is about 25%-30% that is correct of those AmEx SDs. Most of the others are just pure speculations. Or clueless.