Republican presidential nominee Donald Trump declared a US$916 million loss on his income tax returns in 1995, the New York Times reports.
The newspaper said the tax deduction was so major, it could have allowed him to legally avoid paying federal income taxes for up to 18 years.
The New York Times said it had obtained the 1995 records from an anonymous source which had never previously been disclosed.
It says the tax benefits came from the "financial wreckage" of three mismanaged casinos in Atlantic City, Trump's purchase of the Plaza Hotel in New York and his "ill-fated foray into the airline business".
The New York Times wrote: "Although Mr Trump's taxable income in subsequent years is as yet unknown, a US$916 million loss in 1995 would have been large enough to wipe out more than US$50 million a year in taxable income over 18 years."
A statement from Trump's campaign did not confirm or deny whether he filed a US$916 million loss in his 1995 tax returns.
The statement claimed that the documents were "illegally obtained" in what it said was "a further demonstration that the New York Times, like establishment media in general, is an extension of the Clinton Campaign, the Democratic Party and their global special interests."
"Mr Trump is a highly-skilled businessman who has a fiduciary responsibility to his business, his family and his employees to pay no more tax than legally required. That being said, Mr Trump has paid hundreds of millions of dollars in property taxes, sales and excise taxes, real estate taxes, city taxes, state taxes, employee taxes and federal taxes. Mr Trump knows the tax code far better than anyone who has ever run for President and he is the only one that knows how to fix it."
The subject of Trump's taxes came up during last Tuesday's first presidential debate.
Democrat Hillary Clinton attacked Trump for refusing to release his tax returns. Trump has repeatedly said he will not disclose them until an audit of them is completed.
Clinton said during the debate "maybe he doesn't want the American people, all of you watching tonight, to know that he's paid nothing in federal taxes".
She added: "The only years that anybody's ever seen were a couple of years when he had to turn them over to state authorities when he was trying to get a casino license, and they showed he didn't pay any federal income tax," Clinton said.
"That makes me smart," Trump replied.
- Herald Online