Sheldon Adelson, the gaming tycoon behind Las Vegas Sands, has fallen 175 places in the US rich list.
Last year, he was placed at number three, with only Microsoft founder Bill Gates and investor Warren Buffet placing above him.
However, Mr Adelson's company is now in trouble and he needs to raise $4 billion to restart stalled projects across the world.
He told the BBC that he has had to take money from his children's trust fund to buy up his own shares.
"Three months ago, when our stock was $3, I took money out of my children's trust fund, and I bought almost $40 million more of our shares on the open market," he revealed.
Among the schemes that need financial backing are the $12 billion casino complex in Macau and the $5 billion casino and convention space in Singapore.
Divya Panickar, of the Singapore tourist board, recently announced that the Marina Bay Sands project in Singapore would proceed as planned, as would the Sky Park Hotel, reports Travel Weekly.