New York Times, in a well-researched piece on Trump’s “mathematical sleight of hand” that helped him report a $916 billion loss in the early ’90s:

But Mr. Trump’s audacious tax-avoidance maneuver gave him a way to simply avoid reporting any of that canceled debt to the I.R.S. “He’s getting something for absolutely nothing,” John L. Buckley, who served as the chief of staff for Congress’s Joint Committee on Taxation in 1993 and 1994, said in an interview.

[…]

“He deducted somebody else’s losses,” Mr. Buckley said. By that, Mr. Buckley meant that only the bondholders who forgave Mr. Trump’s unpaid casino debts should have been allowed to use those losses to offset future income and reduce their taxes. That Mr. Trump used the same losses to reduce his taxes ultimately increases the tax burden on everyone else, Mr. Buckley explained. “He is double dipping big time.”