A 540 percent surge in Oracle shares in the past year and a 7 percent decline in Microsoft stock--partly caused by uncertainty from its landmark antitrust trial--has moved Ellison to within $8 billion of leapfrogging Gates. Last year, Gates led Ellison by a comfortable $70 billion, according to Forbes' list of the richest people.
A modest slide in Microsoft shares, coupled with a slight climb in Oracle shares--which could occur any day--would leave Gates playing second fiddle to Ellison.
"I don't know Bill, but Larry would take immense satisfaction in having overtaken Bill in terms of net worth," said Mike Wilson, author of "The Difference Between God and Larry Ellison: God Doesn't Think He's Larry Ellison."
The duel between Ellison, 55, and Gates, 44, is one of the most acrimonious and public of any in American business. So the possibility that Ellison could supplant Gates is particularly noteworthy.
"Larry has always tried to portray himself as Bill's rival," Wilson said. The comparison helped Ellison during Oracle's more obscure days, when the two companies operated in different spheres.
According to the October edition of Forbes, Bill Gates was the world's richest man last year, with a net worth of $85 billion. Ellison trailed badly with a relatively paltry $13 billion.
But according to the most current Securities and Exchange Commission records of the technology titans' holdings, Gates is sitting on 742 million Microsoft shares worth just under $60 billion, based on today's closing price of $80.56. Ellison's 663 million shares of Oracle, meanwhile, are valued at more than $52 billion based on today's closing price of $78.94.
If Microsoft shares were to dip 9 percent to about $73, and Oracle's shares were to climb 5 percent to $83, then Ellison's stake would be worth about $55 billion and Gates would trail at $54 billion.
Is such a scenario possible? Yes.
Both companies' stock prices already reached those levels just last week, but on different days. Oracle shares were trading at about $83 last Monday, and Microsoft shares dipped as low as $73 yesterday.
The most common method for calculating the net worth of billionaires is to look at the millions of shares they hold in the public companies they founded. As a result, the calculations do not include other investments or assets these billionaires hold.
Ellison, for example, has 19 million shares of Oracle spinoff Liberate Technologies, which are valued at more than $600 million. Gates also has untold riches in investments and assets that are not publicly known.
In addition, Gates has made highly publicized donations of billions of dollars.
The recent weakness in Microsoft shares is due largely to the antitrust suit hanging over the company. In the most recent blow, settlement talks with the Justice Department broke down and a judge issued a scathing ruling that Microsoft is an abusive monopoly.
Ellison has not wasted any time jumping into the fray. Early in the drawn-out court proceedings, he dubbed Gates the "PC pope" because of his company's dominance over who is allowed to build PCs. More recently, Ellison last December told reporters at his mansion in the posh Pacific Heights neighborhood in San Francisco that he believes Microsoft should be broken into three companies.
Gates, meanwhile, has disparaged Ellison's idea of a slimmed-down network computer. But the company that Ellison formed to launch such a device, Network Computing Incorporated, has since changed its name to Liberate Technologies and has been warmly received by investors--adding hundreds of millions to Ellison's coffers.
Two years ago, Ellison was slinging barbs during a keynote address at Comdex in which he mocked a white paper by Gates that described a world where applications and data would one day reside on big computers.
"We agree. We're in the megaserver business," Ellison said at the time. "Bill's vision of the future is today's Internet. That's how the Internet works, Bill."
Gates' well-known competitiveness could cause him to chafe at losing to Ellison in the battle of the billionaires. But not everyone agrees.
Losing the title may not bother Gates, who could be focused on raising a family and fighting the government, said J. Richard, senior managing director of J. Richard & Co., a compensation firm that focuses on tech companies.
"I would guess that it's not going to be a big deal to Gates," Richard said. "He's past that and grown out of it...He's sort of been there, done that. It's in the same way Warren Buffet didn't care when Gates passed him seven years ago."
News.com's Jeff Pelline contributed to this report.