NEW YORK (CNNMoney.com) - Oracle Corp. CEO Larry Ellison, one of the world's richest men, has managed to run up more than $1 billion in debt, sparking concern from his financial advisor, according to a published report.

The San Francisco Chronicle, citing documents recently unsealed in a shareholder lawsuit against Ellison, reports that Ellison had as much as $1.22 billion in loans against the value of his Oracle stock in 2001, using the proceeds to finance his lavish lifestyles, including homes and yachts.

Ellison's $194 million yacht Rising Sun, at 452 feet long the world's largest private yacht.

"I'm worried, Larry ..." Ellison's accountant, Philip Simon, wrote to his billionaire client in a 2002 e-mail quoted by the newspaper. "I think it's imperative that we start to budget and plan."

The newspaper reports that a document from Simon detailing Ellison's 2000 debt load shows that the Oracle (Research) founder was spending about $20 million a year on miscellaneous lifestyle expenses and accruing about $75 million a year in interest on the loans, as well as $25 million a year on a Japanese villa.

He also spent $194 million over three years on a new yacht and $80 million over the same period on supporting his America's Cup yacht racing team, according to the report.

Even with his spending and debt levels, Ellison remains one of the world's richest men. Forbes magazine puts his net worth at $18.4 billion, making him the No. 4 richest American and the ninth richest man in the world. And despite the warnings from Simon, Ellison apparently didn't view his way of operating as risky, according to the Chronicle, which cites a court document quoting him as pointing out that his net worth was always at least 10 times his debt.

Simon was pushing Ellison to retire debt and diversify his holdings. The most recent Oracle proxy statement shows Ellison owning 1.3 billion shares of Oracle as of Aug. 15, almost a quarter of the shares outstanding. Those Oracle shares are worth $16 billion at current prices.

Ellison was apparently reluctant to sell his Oracle shares, although the newspaper reports that he sold more than 29 million Oracle shares in January 2001, generating nearly $900 million. That sale, which the paper reports came just weeks before Oracle issued a disappointing earnings statement that sent shares sharply lower, prompted a shareholder lawsuit. That lawsuit generated the documents cited by the newspaper.

The newspaper reports Ellison argued in the lawsuit that the stock sale wasn't because he thought Oracle's stock would soon decline in price but because Simon had been pressuring him to unload some of his vast company holdings. The suit was settled with Ellison donating $100 million to charity and paying $22 million to lawyers, although one of the plaintiffs is appealing the settlement, the newspaper reports.

For a closer look at the super-yachts of Ellison and other CEO's, click here.