Profit from those businesses added as much as $300 million annually to the foundation's endowment, O'Clery said. In 1997, the foundation received about $1.6 billion after Feeney's share of Duty Free Shoppers Group was sold, he said.
Feeney decided to acknowledge his philanthropy to encourage other wealthy donors to do the same, O'Clery said.
"He wanted his model of giving while living to be out there for other people of great wealth to use as a template," the author said.