In 1993, Holt decided to invest in the San Antonio Spurs, wanting to help keep the team in San Antonio. He and his wife Julianna became the team's principal owners.
Holt and the Spurs organization later purchased other franchises – the Austin Toros of the NBA Development League, the San Antonio Rampage of the American Hockey League, and the renamed San Antonio Silver Stars of the WNBA. With each purchase, the team colors were changed to silver and black, the motif used by the Spurs.
To keep the team in San Antonio, Holt led a successful effort to build a new arena, the AT&T Center, through a ballot measure that would provide public funding for its construction. The new home to the Spurs and the San Antonio Livestock Exposition broke ground in August 2000 and opened for the 2002 season. During his tenure as owner, the Spurs won five championships in 1999, 2003, 2005, 2007, and 2014.
Holt retired in 2016, and his wife, Julianna, succeeded him.