Antoine Walker has become a posterboy for squandering a pro sports fortune. The former NBA star famously earned $108 million over his successful NBA career but retired almost penniless.

Two years after leaving the NBA, Walker filed for bankruptcy.

Theories for his financial fallout abound. Rumors swirled of Walker's intense gambling habits, as well as his tendency to give money to greedy relatives.

But Walker revealed to CNN Money that the truth is far simpler -- and more understandable: his investments went belly-up.

Walker had invested heavily into real estate, he tells CNN, and at maybe the worst time in history to be doing so.

"We got caught in the recession. We had a ton of undeveloped real estate," Walker tells CNN. "It went bad. The banks wanted their money back."

Compounding those failures was that Walker borrowed money against his own personal collateral. When his investments failed, he had to pay $20 million of his own money to the banks.

Walker, who played for the Boston Celtics in his prime but also won an NBA championship with the Miami Heat, did have family members come to him seeking financial advice -- about 30, he tells CNN.

His story has become a cautionary tale that the NBA teaches to incoming rookies at an annual rookie camp designed to instill better spending habits and to help those players make better decisions as professional athletes.

But Walker's family borrowing didn't cause nearly the amount of financial ruin as previously thought.

Walker, to his credit, has put himself back together financially. He now works for Morgan Stanley as a financial adviser to help athletes avoid making his same mistakes.

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