"Even in the world of high finance, this court cannot endorse a proposition that finds a misstatement of at least $812 million dollars to be 'immaterial,'" he wrote.
The judge said Trump's overvaluations included his Mar-a-Lago estate in Florida, his penthouse apartment in Manhattan's Trump Tower, and various office buildings and golf courses.
He took particular issue with Trump's claim that the penthouse was 30,000 square feet (2,787 square meters), nearly three times its actual size, resulting in an overvaluation of as much as $207 million.
"A discrepancy of this order of magnitude, by a real estate developer sizing up his own living space of decades, can only be considered fraud," Engoron wrote.
The judge said Trump also grossly overvalued Mar-a-Lago, estimating it was worth as much as $612.1 million, though an assessor said its market value was no more than $27.6 million.