The

, a Quaker day and boarding school in Newtown, Bucks County announced today that it will receive what is believed to be one of the largest gifts to an existing private school in U.S. history: $128.5 million.

The donation from a grateful alumna tops the record-setting $100 million that Walter Annenberg gave to his alma mater, the Peddie School in Hightstown, N.J., in 1993.

Barbara Dodd Anderson, who graduated from the George School in 1950, said the donation would honor her father, the late David Dodd, an economist and professor at Columbia University School of Business, as well as George School teachers.

Dodd had been a professor, friend and business partner of Warren Buffett, the philanthropist and billionaire chairman of Berkshire Hathaway Inc., the Omaha-based holding company.

Dodd bought Berkshire Hathaway shares in the early days, when it was a textile firm, and put those shares in his daughter's name. As a result, Dodd Anderson became one of the early investors in what has become a multi-billion dollar enterprise.

"This gift is meant to honor not only my father, David Dodd, and his legacy, but also all of the teachers at George School who had such an impact on me and are so important to their students today," Dodd Anderson said in a statement. She lives in Northern California and did not attend today's event.

"I want to help George School because of the excellence of its faculty and because it is a school without pretensions, where caring for and learning from each other are as important as academic success," she said.

The money will be provided to the school over 20 years through an irrevocable lead trust. School officials said the initial funds will be used to boost student financial aid, increase compensation for faculty and staff and for environmental sustainability.

"Barbara's gift will help us to uphold our position of leadership in the area of student financial aid, and through it our deep and long-standing commitment to socioeconomic diversity," said Nancy Starmer, head of school.

Trustees learned of Dodd Anderson's gift over the weekend. Students, faculty, staff, parents and alumni were told  last night.

Buffett, who in June 2006 made a commitment to give his own vast fortune to charity, praised Dodd Anderson's gift.

"Any longtime shareholder of Berkshire is appreciably wealthier because of the indirect influence that David Dodd had upon our company," Buffett said in a statement released by George School. "I am delighted that his decision to invest in Berkshire has enabled Barbara to honor both her father and George School through this wonderful gift."

This is not Dodd Anderson's first gift to George School, which has a hefty $77.2 million endowment. Among other things, she established the David LeFevre Dodd Teaching Chair in her father's honor to attract and keep great teachers. She created a scholarship in her own name for students who are committed to academic excellence and social involvement. And she provided a $5 million leadership gift for a new library.

Founded in 1893, George School enrolls 540 day and boarding school students from ninth through 12th grades both from throughout the region and around the world. Tuition is $37,500 for students who board and $27,750 for day students who commute to the 265-acre campus.

Contact staff writer Martha Woodall at 215-854-2789 or at martha.woodall@phillynews.com