Bezos, 57, gained $8.4 billion in net worth on Tuesday alone, according to the Bloomberg Billionaires Index, as Amazon stock soared 4.7 percent on the Pentagon's announcement that it is canceling the $10 billion JEDI contract with Microsoft.
It vaulted Bezos above the previous record of $210 billion, held briefly in January by Tesla CEO Elon Musk, who has seen his fortunes decline and now holds a mere $181 billion, putting him in distance second after Bezos.
While Tesla stock has declined nearly 10 percent so far this year, Amazon shares have continued to soar, adding 15.4 percent since January 1.
Amazon's soaring shares have boosted the fortunes of Bezos, who on Monday stepped down as chief executive of Amazon, handing over the reins to his experienced lieutenant Andy Jassy.
Bezos now takes over the role of executive chairman at Amazon. He still owns about 51 million shares of Amazon stock, a position that makes up the vast majority of his wealth.
His gains on Tuesday broke the record for wealth since the Bloomberg index began tracking billionaire net worth in 2012, making Bezos the richest man in modern history.
Adjusted for inflation, historical figures such as the 19th Century's John D. Rockefeller (worth $350 billion in modern dollars) could be considered richer.
Deeper in history, some historical leaders controlled wealth that is nearly incalculable. Mongol warlord Genghis Khan, for example, had a peak net worth that is estimated in the hundreds of trillions of dollars.
Amazon stock rose sharply on Tuesday after the Pentagon canceled a contract with Microsoft that was forged under the Trump administration.
The contract has been on hold after Amazon filed a lawsuit challenging the decision under then-President Donald Trump, alleging that the former president exerted improper pressure on military officials to steer the contract away from Amazon.
Amazon argued that the deal was tainted by politics, particularly Trump's antagonism toward Bezos, who owns the Washington Post.
Amazon said in 2019 the Pentagon decision was full of 'egregious errors,' which it suggested were a result of 'improper pressure from Trump.'
The company cited a 2019 book that reported Trump had directed the Defense Department to 'screw Amazon' out of the JEDI contract.
The contract for cloud-computing service could eventually have been worth $10 billion for Microsoft.
Instead, the Pentagon will pursue a deal with both Microsoft and Amazon and possibly other cloud service providers.
'With the shifting technology environment, it has become clear that the JEDI Cloud contract, which has long been delayed, no longer meets the requirements to fill the DoD´s capability gaps,' the Pentagon said in a statement.
Shares of Microsoft and Amazon both closed at a record high with the online retailer up 4.7 percent and shares of the software firm a penny higher.
Michael Pachter, an analyst with Wedbush Securities, said the absolute dollars involved - $10 billion over a decade - are at most a nice-to-have for the cloud companies, with AWS alone generating $45.3 billion in sales and $13.5 billion in operating profits for 2020.
The real value, he said, was in showcasing the security of the clouds, 'but it's not going to move the needle' for either company.
Ultimately, the cancellation and new contract could benefit Microsoft, Moerdler said, because the Redmond, Washington-based company has had nearly two years during the legal wrangling to invest in its technology.
'If there is now another competition, Microsoft is going in from a better position,' Moerdler said.
As recently as September the Defense Department re-evaluated the contract proposals and said Microsoft's submission was the best.
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