Ball told ESPN on Friday that he believes Foster, who owns 16.3 percent of Big Baller Brand, previously "used his access to my business and personal finances to enrich himself. As a result, I have decided to sever all ties with Alan, effective immediately."
Foster couldn't account for about $1.5 million from Ball's personal and business banking accounts, according to ESPN.
Harrison Gaines, who is Ball's current agent, released a statement and said he will be taking a larger role in the Lakers guard's career due to the allegations against Foster.
"This is a stunning development and very unfortunate situation for all involved," Gaines said. "Due to the Ball Family's business structure, my interactions with Alan Foster were very limited.
"I had one responsibility: manage the employment of Lonzo with the Los Angeles Lakers and guide his younger brothers in the pursuit of their basketball aspirations. At best, I was on the periphery of the rest of the Ball Family businesses.
"This is a cautionary tale and I'm glad Foster's actions have been discovered. Lonzo has now empowered me to take a more active role in his career. I look forward to continuing as his agent and providing guidance that will support his growth as a person and player."
Foster has served as the business manager of all of the Ball family's businesses, including Big Baller Brand, which formed as a limited liability company in 2014. Documents and emails showed Foster had been questioned by Ball's financial adviser regarding his business decisions and communication last fall. Ball's personal taxes and Big Baller Brand's taxes couldn't be finished on time because $1.5 million was unaccounted for, according to ESPN.
Lonzo Ball raised concerns about Foster to his father, LaVar Ball, multiple times in the last few months. LaVar Ball reviewed the documents and emails from Lonzo Ball's adviser this week, calling the situation "devastating," according to ESPN.
"I've always believed in the best in people. Regretfully, I put my complete trust in Alan Foster to manage my son's business affairs," LaVar Ball said. "At the end of the day, family comes first, and I support Zo wholeheartedly. Together, we will make this right."
Foster has been friends with the Ball family since 2010. Foster's son and Lonzo Ball developed a friendship while in middle school. Foster has been the manager of Big Baller Brand since 2016.