It's a large portion of major donations. If Bob Johnson donates $20M to a hospital to create the Johnson Cancer Wing, he is in benefiting himself: he is buying

It's a large portion of major donations. If Bob Johnson donates $20M to a hospital to create the Johnson Cancer Wing, he is in benefiting himself: he is buying his name on a building. If Bob donates $20M to a local symphony orchestra that he attends, he is benefiting himself by buying better music for him to listen to. If Bob donates $20M to a candidate for office whose policies would ultimately benefit Bob, well... I wouldn't call these bribes. But they're less like donations and more like purchases.