Mento, Steve Dayton is richer then Wayne or Lex. And I think that Lex is a bit richer then Wayne. He is an president. Archangel is also quite rich. Richer then Xavier. Emma Frost owns Frost Enterprises, so she has some money also. I think that the list goes like this:
1. Steve Dayton
2. Victor Von Doom
3. Lex Luthor
4. Tony Stark
5. Bruce Wayne
6. Warren Worthington
7. Emma Frost/Charles Xavier
Black Panther, I don't know if he has as much money, per se, as Stark, but he has just as much influence if not more. T'Challa wrecked the world's economy with a phone call, that's how much money and how many assets he controls, if not directly.
Namor, as Crown Prince of the Realm Eternal, he commands 70% of the world, that means he has access to untouched natural resources, and owned Oracle Inc. for awhile, before selling it after he rid himself of surface world affairs.