https://thinkprogress.org/congress-had-a-chance-to-get-trumps-tax-returns-republicans-voted-it-down-bf317b718550#.pjj4o2a8l
"Unlike all but one Presidential nominee since Nixon, Trump has not released his tax returns to the public (Gerald Ford, the one nominee who didn’t, released a summary). Trump has also, unlike every other modern president, refused to divest from his business holdings. According to the financial disclosures that he was required to file, however, Trump has a stake in 564 companies around the world. Many of his businesses work in or with foreign countries. Those dealings almost certainly put Trump in violation of the Constitution’s emoluments clause. Without his tax returns, however, the true extent of Trump’s financial entanglements is unknown."