The South Dakota business community is mourning the passing of T. Denny Sanford, the billionaire founder and owner of First PREMIER Bank, who died at the age of 90. His death was announced on Saturday, July 18, by South Dakota Governor Larry Rhoden. At the time of the announcement, no cause of death had been disclosed.
Sanford’s passing marks the end of an era for one of South Dakota’s most influential businessmen and philanthropists. Throughout his career, he transformed the banking industry while donating billions of dollars to healthcare, education, and charitable causes that will continue to benefit future generations.
A Banking Pioneer
T. Denny Sanford built his fortune as the founder of First PREMIER Bank and PREMIER Bankcard, a Sioux Falls-based financial institution that became one of the nation’s largest issuers of Mastercard credit cards, particularly serving customers with limited or damaged credit histories.
Despite operating a relatively small branch network, the bank grew into one of the country’s leading credit card issuers, making Sanford one of South Dakota’s wealthiest individuals.
According to Forbes, Sanford’s estimated net worth stood at approximately $2.4 billion in 2026, following a peak of more than $3 billion in 2022.
A Legacy of Philanthropy
Beyond his success in banking, Sanford was widely recognized for his extraordinary charitable giving. His donations transformed healthcare, education, medical research, and children’s services throughout South Dakota and across the United States.
His contributions helped expand Sanford Health, which became one of the nation’s largest rural healthcare systems. He also made significant investments in medical research, children’s hospitals, universities, and community initiatives.
Governor Larry Rhoden described Sanford as “the greatest philanthropist in South Dakota history,” noting that his generosity permanently changed the state.
Sanford Health President and CEO Bill Gassen also paid tribute, crediting Sanford’s vision and generosity with helping advance medical care and research that will benefit patients for generations.
Family
T. Denny Sanford was previously married to Colleen Anderson Sanford from 1995 until their divorce in 2005. Although they later divorced, the two reportedly remained close friends until Colleen’s passing in 2025.
He is survived by his two children, along with extended family and many friends and colleagues.
Cause of Death
At the time of publication, the official cause of T. Denny Sanford’s death has not been publicly released. No reports had indicated that he was suffering from a serious illness prior to his passing.
Final Tribute
T. Denny Sanford will be remembered as a visionary entrepreneur, pioneering banker, and one of America’s most generous philanthropists. His influence extended far beyond the financial industry through his commitment to improving healthcare, education, and the quality of life for countless individuals.
His legacy will continue through the institutions he built, the lives he transformed through philanthropy, and the lasting impact of his generosity on South Dakota and beyond.
Rest in peace, T. Denny Sanford. His remarkable legacy of innovation, generosity, and service will be remembered for generations to come.