BESIDES HIS usual brazenness, something unsettling lurks behind Donald Trump’s latest statement that — unlike every other nominee in modern times — he will not make public his tax returns before the November election. “There’s nothing to learn from them,” he told the Associated Press. Earlier, he claimed he could not release his returns because he was being audited. Then he said on Twitter they would be released “when audit is complete, not after election!” To voters considering his fitness to be president, Mr. Trump’s response is that he will be the judge and jury, a paternalistic and insulting attitude toward the public.

In fact, there would be much to learn from Mr. Trump’s tax returns and, more broadly, his years as a businessman. We’re not picking this criterion out of thin air; Mr. Trump is the one who repeatedly trumpets his business experience as his qualification for the presidency. His boasting ought to be tested against hard information about how his companies performed, how they were managed and governed, how shareholders and bondholders were treated, how Mr. Trump was compensated, how he managed his tax burden and to what extent he has been a philanthropist. Unfortunately, Mr. Trump’s companies have been largely private in recent years, shielding his accounts from public scrutiny. He did file a 92-page personal financial disclosure statement with the Federal Election Commission that was accompanied by a news release claiming Mr. Trump’s net worth is “in excess of TEN BILLION DOLLARS.” The capital letters are his. Mr. Trump claimed in the news release that his income for 2014 was $362 million, although Fortune magazine, scrutinizing it, reported that that figure is actually his revenue not his income, which would factor in expenses, and the magazine mused, “You would think that a successful businessman would know the difference between revenue and income.” Based on Mr. Trump’s known revenues, Fortune calculated, there is no way he is worth $10 billion or more. It wouldn’t be his first big fib.

We also would be curious to see Mr. Trump’s deductions for charitable contributions, given reports in The Post that his philanthropy has been expressed not in monetary donations from Mr. Trump but in conservation easements, donations of land and free rounds of golf given by his courses for charity auctions and raffles. It also would be fascinating to see how Mr. Trump managed his tax load, including if he used offshore shelters.

Much of what is known about Mr. Trump’s business career suggests he has bullied and bulldozed his way to such success as he has had and, at times, defaulted on interest payments to bondholders and put his companies through bankruptcy. Did he create real value or just personal notoriety? If he has nothing to hide, he should put the facts out.