Pauline MacMillan Keinath

Pauline MacMillan Keinath (born July 31, 1934, in Hennepin County, Minnesota) is an American billionaire heiress. She is believed to be the largest individual shareholder in Cargill.

Wealth As of March 2026, she had a net worth of $9.5 billion from an inherited 9% stake in Cargill.

In 2014, she was the 16th richest woman in the US.

Family She is a great-granddaughter of William Wallace Cargill, the founder of Cargill, the largest private company in the US. Her father was Cargill MacMillan Sr. (1900–1968). She has two siblings, Whitney MacMillan (1929–2020) and Cargill MacMillan.

She is married, with four children, and lives in St. Louis, Missouri.

In 2023, the family of Pauline MacMillan Keinath were the largest donors to Andrew Bailey's run for Missouri Attorney General, having contributed $375,000 to the Life and Liberty PAC.