In 1998, there was another larger doner to society. Professor Donald Othmer and wife Mildred left their $800 million estate to various Brooklyn and other organizations. From this article, their wealth was built based on BRK stock purchases.

cbsnews.com - Quiet couple has fortune

Professor Donald Othmer and his wife, Mildred, lived modestly. They had a townhouse in Brooklyn. They rode the subway. And when they decided to invest, they entrusted their money to an old friend from Nebraska.

The friend happened to be Wall Street whiz Warren Buffett.

The Othmers' road to riches began in the 1960s, when they each invested just $25,000 with Buffett. In the early 1970s they received shares in Berkshire Hathaway, Buffett's investment and insurance holding company.

At the time, the shares were worth $42. Thanks to the booming stock market and Buffett's acumen, the stock now is worth $77,200 a share.

The result, when the Othmers died, was an estate worth a whopping $800 million, one-quarter of which will go to Polytechnic University in Brooklyn, where Othmer taught for nearly 60 years.

Other beneficiaries of the Othmers' estate are institutions the couple supported throughout their lives.

Long Island College Hospital in Brooklyn, where Othmer served as a board member, is set to receive $160 million; the University of Nebraska-Lincoln, from which both graduated, is to get $140 million; and the Chemical Heritage Foundation of Philadelphia is to receive $125 million.

Planned Parenthood of New York City, on whose board Mrs. Othmer served, will receive about $75 million. The Brooklyn Historical Society was left $16 million and the Omaha Board of Education, $12 million.

BRK.A stock price at the time of this article was $77,200. So the donations were equal to 10,363 A shares.

At today's prices, that would equal some $6.3 billion in gifts.

From the article, both Othmers were graduates of the University of Nebraska in Lincoln. And were friends of Buffett.

When I first learned of this, something about the name Othmer rang a bell with me. I finally realized that he was the co-author of the Kirk-Othmer Encyclopedia of Chemical Technology. That was a standard reference for chemical engineers back in the days before the internet. I received my degree in 1955.