A published report that Donald Trump took a nearly $1 billion loss on his taxes has lit up the political world — but experts say the details are so opaque that it’s possible he may not have lost actual money at all.

The report, from The New York Times, said Trump’s tax loss “was derived from the financial wreckage he left behind in the early 1990s through mismanagement” of 3 Atlantic City casinos, the airline business and his purchase of the Plaza Hotel. The Clinton campaign is using it to criticize Trump’s business acumen.

Trump himself says the report demonstrated his knowledge of the tax code.

The New York Times based its analysis on the first page only of three state tax returns – New York State, where Trump lives, Connecticut and New Jersey. The majority of Trump’s 1995 bottom line net loss is driven by a $909 million loss labeled “other income.”

“The other income line is a catch-all that could include lots of other things not appearing elsewhere,” says Robert Thesman, a Washington state CPA who specializes in real estate tax issues, “including any non-wage, non-business or non-investment income, even gambling losses.”

Losses shown on the tax return are not the same as cash losses or even financial losses, says Andrew Schmidt, a professor of tax and accounting at North Carolina State University.

The $909 million negative amount shown on the 1995 tax returns on the other income line may not be all net operating losses, and could have been caused by many activities that have no cash flow effect and that aren’t scandalous at all. A huge first year depreciation expense on a very leveraged asset such as a new casino or hotel could be such an example, says Thesman.

Depreciation is a tax expense but does not require a cash outlay. In addition, says Thesman, “the NOL carryforward amount was created in a prior year, but we don’t know when from looking only at these pages from state returns.”

The New York Times published correspondence from New Jersey regulators that says the net operating losses go back to at least 1991.

“We don’t know what Trump’s average annual taxable income was before and after 1995 so we don’t know how quickly he could use up the total loss allowance or how many more years he had left by 1995 to use it,” said Schmidt.

The effect of net operating losses on state income taxes varies, depending on each state’s tax regime. For example, the New Jersey state return shown by the New York Times on their site does not reflect the negative $909 million amount at all. That’s because New Jersey does not allow the carryback or carryover of losses.

Trump’s 1995 New Jersey tax return actually shows taxable income of $19.55 million and shows he overpaid his New Jersey state tax by $45,800.

See also: Opinion: Donald Trump misplayed his tax hand — badly