Phil Mickelson reportedly lost $40 million from gambling over a 4-year period, according to a new book

During a stretch of Phil Mickelson's career where he was making plenty of money, he was reportedly losing tens of millions from gambling.

• Phil Mickelson lost $40 million from gambling between 2010-14, according to a new book.
• Mickelson's breakup with longtime caddie Jim "Bones" Mackay also reportedly stemmed from money issues.
• "Phil: The Rip-Roaring (and Unauthorized!) Biography of Golf's Most Colorful Superstar" was written by Alan Shipnuck and is set for release on May 17.

Phil Mickelson had gambling losses totaling $40 million between 2010 and 2014, according to a new biography of the golf superstar.

Alan Shipnuck, author of the forthcoming book "Phil: The Rip-Roaring (and Unauthorized!) Biography of Golf's Most Colorful Superstar," published an excerpt on the Fire Pit Collective Thursday, revealing both the extent of Mickelson's gambling losses and how his financial issues related to his breakup with longtime caddie Jim "Bones" Mackay.

According to Shipnuck, Mickelson's finances were audited as a part of the investigation into accusations of insider trading against him in 2014. 

Per Shipnuck:

"According to a source with direct access to the documents, Mickelson had gambling losses totaling more than $40 million in the four-year period (2010–14) that was scrutinized.

"In those prime earning years, his income was estimated to be just north of $40 million a year. That's an obscene amount of money, but once he paid his taxes (including the California tariffs he publicly railed against), he was left with, what, low-20s? Then he had to cover his plane and mansion(s), plus his agent, caddie, pilots, chef, personal trainer, swing coaches and sundry others. Throw in all the other expenses of a big life — like an actual T. Rex skull for a birthday present — and that leaves, what, $10 million? Per the government audit, that's roughly how much Mickelson averaged in annual gambling losses."

Shipnuck also writes that financial issues were at the heart of Mickelson's breakup with longtime caddie Jim "Bones" Mackay. While Mickelson and Mackay kept things relatively amicable publicly, according to Shipnuck, it was Bones that dropped Mickelson over "a series of simmering grievances (laid out in detail in the book), including hundreds of thousands of dollars in overdue back pay."

It's not the first time Shipnuck's book has made headlines in the build-up to its release, due out May 17. Earlier in the year, the longtime Sports Illustrated and Golf magazine scribe wrote up an interview he conducted with Mickelson in late 2021, in which Mickelson called the Saudi government, with whom he was directly working on developing a new golf league, "scary motherfuckers."

Mickelson has not played a PGA Tour event since his comments to Shipnuck became public in mid-February, most notably missing the Masters, a tournament he has won three times.

Meanwhile, the Saudi Golf League, now operating under the name LIV Golf, is set to host its debut tournament this June in London, with seven more events planned for the 2022 season.

Mickelson has reportedly submitted a request for release to the PGA Tour so that he can play in the tournament; he has also registered for the upcoming U.S. Open and PGA Championship.