Susie Buffett, the wife of billionaire investor Warren Buffett,died yesterday after suffering a stroke while visiting friends in Cody,Wyo., Mr. Buffett’s company announced.

She was stricken Wednesday at the ranch of Herb Allen, a family friend.

Mr. Buffett, the chairman of Omahabased Berkshire Hathaway Inc., was with his wife when she died, the company said.

Susie Buffett, 72, was a director at Berkshire and stood to inherit her husband’s fortune. Mr. Buffett has said his stock in Berkshire, valued at about $42.9 billion, would go to his wife upon his death and then to a foundation. She was a formidable presence at Berkshire’s annual shareholder meeting.

Mr. Buffett, who lives in Omaha, and fellow Nebraskan Susie Thompson were married in 1952. They had three children, and remained friendly, but had lived separately since the late 1970s.

While Susie spent much of her time in San Francisco, the Buffetts often traveled and spent time together. She often joined Mr. Buffett and his friends in song.

Susie was treated for mouth cancer last fall, and it was announced last week that Warren and Susie Buffett donated $6 million to five California medical specialists who coordinated the treatment. Doctors had said she was doing “extremely well” after the surgery and radiation therapy that followed. Susie had recently returned from a trip to France.

The Buffetts had three children: Susie, 50, who lives in Omaha; Howard, 49, who lives near Decatur, Ill., and who also is on Berkshire’s board, and Peter, 46, a musician living in Milwaukee.

Friends remembered Susie Buffett yesterday as a “joyous and naturally compassionate” person. One longtime acquaintance noted, “She took in stray cats, large and small.”