Billy Walters is one of the biggest, most notorious sports gamblers in United States history, and he wrote in his book Gambler: Secrets From A Life At Risk, co-authored by Armen Keteyian, that Phil Mickelson placed over $1 billion in bets in his lifetime.
"I don't know anyone individually that has ever bet more than Phil Mickelson," he told Darren Rovell of the Action Network.
This article will be updated soon to provide more information and analysis.
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