Richard C. Blum, a financier and major donor to Democrats — largely to his wife, Senator Dianne Feinstein of California — died March 27 at the family home in San Francisco. He was 86.

Mr. Blum ran his own investment firm, Blum Capital Partners, and during his career as an investment banker and financial manager, his clients included large institutions. With deep pockets, he became a major figure in Democratic politics. His net worth was estimated to exceed $1 billion.

He also held nonprofit positions; at one point he was chairman of the University of California Board of Regents. With the Dalai Lama among his influential friends, Mr. Blum developed an interest in South Asia as the home of Buddhist philosophy, as a recipient of philanthropy, and as a place for adventure. He once led an expedition up part of Mount Everest. In a statement of condolence, President Joe Biden called Mr. Blum “a successful businessman and proud son of California, who dedicated much of his public life to fighting poverty around the globe” through the establishment of the American Himalayan Foundation, a nonprofit group that builds schools and hospitals in Tibet, and the Blum Center for Developing Economies at the University of California, Berkeley, which focuses on innovative solutions to global poverty.

During Ms. Feinstein’s 1990 race to be California’s governor, Mr. Blum described to The New York Times what he called the triathlon of politics: “No. 1,” he said “we get to see on a regular basis everything she’s ever done and I’ve ever done distorted in the newspapers. No. 2, we get to share 17 years of our tax returns with 30 million people. And three, I get to pay to watch all this happen.”