How We Rank Them

It's not easy to put a figure on a person's generosity. Many charitable donations are given anonymously, with little or no fanfare. The reports of foundations run by individuals are often filed late--and much giving can flow straight from the donor's pockets anyway. So to compile BusinessWeek's first ranking of the most generous philanthropists, we relied heavily on news reports of publicly announced gifts, press releases, foundation filings, and interviews with people in the field of giving. The Top 50 are ranked by what they have pledged or given in the past five years. We also estimate each person's total contributions as well as the percentage of his or her current net wealth that has been given away as a measure of his or her generosity.

To compile a list of possible philanthropic laggards, we started with the most prominent multibillionaires and then looked for news reports and public records of their charitable contributions. The people on our list rarely, if ever, turned up as donors--or gave so little in relationship to their wealth that they appeared miserly. Most of them maintain that they give substantial sums but do so privately. In some cases, we were able to verify significant gifts, and those people were removed from the list (page 94).

To identify the most creative philanthropists, we asked dozens of people in the giving industry to name the most innovative donors (page 90). We screened those candidates and made our selections.

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