Robert Wilson doesn’t do small philanthropy. Whether it’s $22 million to the Nature Conservancy in 2005 or $22.5 million to the New York Roman Catholic Archdiocese in 2007, the retired hedge fund manager has no compunction about giving away gigantic sums. “My aim is to give away 70 percent of my net worth before I die,” he says. All told, his foundations gave away more money than those of any other Wall Street professional, mostly to environmental causes. Considered one of the greatest short-sellers of all time, Wilson sat down with Condé Nast Portfolio’s Duff McDonald to share his thoughts on how, why, and to whom he gives.

What’s your main focus in terms of giving?
My primary interest has been conservation—the idea that but for my money, this building or piece of land or that animal would be gone. To that end, I have been a substantial donor to the World Monuments Fund, which preserves old buildings around the world. I have also given to the Nature Conservancy, which acquires land around the world, and the Wildlife Conservation Society, which is trying to save animals. I’ve given to the Environmental Defense Fund too, though that’s more of an advocacy organization. It doesn’t collect and conserve properties; it’s just trying to save the world so these properties that I am spending money acquiring will be around.

Your donations to the Nature Conservancy ($22 million) and the Wildlife Conservation Society ($13.6 million) in the past year are huge by any standard. Why so big?
Because my aim is to give away 70 percent of my net worth before I die. That’s my strategic plan. We all know there’s no strategic plan that actually works, but you’ve got to have one anyway. By that I mean I don’t know when I will die. Most of my rich friends will probably end up fobbing off their wealth on a foundation that will be run by people who are not nearly as smart as they are and who won’t do what they want them to do. About 10 years ago, I decided that I would like to give away a lot of my money aggressively while I was still alive and not rely on others to do it after I died.

But you did set up a foundation. Why not just write checks to the organizations you support?
The main reason for setting up a foundation is that there are certain tax advantages to giving to a foundation instead of directly to a charity. These are tax wrinkles. The foundation, as such, is a product of the Internal Revenue Code. I also have a trust. The trust is to avoid probate when I die. It can be an expensive thing to die, especially if you live in New York State. All the rich people I know now have trusts rather than regular estates if they live in New York.

Why not just leave the money to your heirs?
Honestly, if I could take it with me, I probably wouldn’t give a dime to anybody. I don’t have any children, but I’m not sure that would be a controlling factor, in any case. I think I would agree with the general feeling among the rich today, which is that it’s acceptable to give enough to their children to make them modestly rich but not so much that they’re filthy rich.