A financial adviser allegedly swiped at least $20 million from NBA All-Star Tim Duncan by forging his signature on investment documents and secretly pocketing other funds.

The 39-year-old Duncan has now filed suit naming Charles Banks as the alleged perpetrator and asserting that the transgressions took place from 2005 to 2013. According to Bloomberg News, Duncan, who has netted earnings in the neighborhood of $220 million over his NBA career, discovered the discrepancies last year while accounting for his assets as part of a financial filing during divorce proceedings.

"Luckily I had a long career and made good money," the 15-time All-Star and two-time league MVP said. "This is a big chunk, but it's not going to change my life in any way. It's not going to make any decisions for me."

The five-time NBA champion hasn't said if he plans to return to the San Antonio Spurs for a 19th season next year. He averaged 14 points and nine rebounds last season.

As for the losses, they constitute roughly 15 percent of Duncan's after-tax career earnings.

"I trusted someone to do a job that I hired them to do and they misused my trust and went astray and started using my money," he said. "I thought, for the most part, I was keeping an eye on things. You have to have people checking on people checking on people. I did that for a while. Obviously, I got to a point where the people I trusted were checking on themselves."

Meanwhile, Banks has previously argued that Duncan became impatient and was simply looking for ways to get out of their partnership. Banks' attorney, Antroy Arreola, adds Duncan "has no claim" against his client.

"I'm a loyal guy," Duncan said. "I'm a man of my word, and I assumed other people would be that way. That's just not the case in life."