Grace Groner worked as a secretary at Abbott Laboratories (ABT) for 43 years, and bought three $60 shares of specially issued Abbott stock in 1935.

That must have been a major purchase back then for a young woman fresh out of college. Little did she know at the time that she had just created what would become a fortune.

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The Chicago Tribune tells the story of Groner, who never married or had children, and lived in a small one-bedroom house until she died in January at age 100.

Those three Abbott shares split over and over for seven decades, and Groner reinvested the dividends, writes John Keilman of the Tribune. The shares became a cornerstone of an estate that, by the time Groner died, was worth $7 million.

She has left the money to a foundation connected to her alma mater, Lake Forest College. The donation is expected to generate more than $300,000 a year for the school, Keilman reports, and will be used to help students with internships and study-abroad programs.

Groner even left her small house in Lake Forest to the school, and it will become a student residence for scholarship winners.

Abbott helped Groner become a millionaire, but her frugal living certainly had much to do with it also. She bought used clothing, and preferred to walk instead of buy a car, Keilman reports. Her home was rather unspectacular, holding plain pieces of furniture, an old television set and mismatched dishes.

Few people knew about her wealth, and the president of Lake Forest College could only say one thing when informed of her donation: "Oh, my God."

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