US casino magnate Sheldon Adelson spent $150 million, much more than previously thought, on funding Republican hopefuls in an unsuccessful bid to stop Barack Obama winning a second term, a report said Monday.
Adelson, 79, whose Las Vegas Sands Corp. also operates casino resorts in the Chinese territory of Macau, the world's largest gambling center, funded several Republican candidates and affiliated groups during the campaign.
His apparent aim was to unseat Obama and help Republican lawmakers take back control of Congress after the November 6 elections, but his spending failed with Obama defeating Mitt Romney and the Democrats retaining the Senate.
The $150 million figure -- given by the Huffington Post, citing Republican fundraisers -- is three times more than the $54 million previously disclosed, and 50 percent more than the $100 million Adelson once said he was prepared to spend.
The money bankrolled groups ostensibly working against Obama and in support of Republican presidential nominee Romney and other candidates who ran for Congress against members of the Democratic Party.
Adelson, whose fortune is estimated at $20 billion by Forbes magazine, is being investigated by the US Justice Department over how his casino network is operated.
Last week, his company reportedly approved a special dividend of $1.2 billion for Adelson and his wife -- they own around 52 percent of Las Vegas Sands Corp. -- in advance of an expected federal tax hike.
The two fundraisers quoted by the Huffington Post said Adelson shelled out between $30 million and $40 million to Crossroads GPS, a campaign group run by Karl Rove, former Republican president George W. Bush's top political aide.
While US law places limits on the amounts that can be given directly to political candidates, a Supreme Court ruling in 2010 allows corporations, unions and individuals to make unlimited donations to arms-length groups.
The Citizens United ruling led to the creation of super-PACS (political action committees), such as GPS, that spent millions of dollars on campaigning though it was not officially endorsed by a specific candidate.