According to a Politico article, New York can force Trump to release his New York State tax returns which are probably similar to his Federal return, listing both in-state and out-of-state sources of income and his charitable contributions.
"The idea is a simple one: Each year, Trump files federal income tax returns with the IRS and a similar resident income tax return with New York. The state form doesn’t include all the same information as Trump’s federal filings, but it includes much of it. Trump’s state returns disclose how much income he earns from in-state and out-of-state sources and what deductions he claims for charitable contributions and various other expenses. If Trump uses phantom losses to zero out his federal income tax liability, he almost certainly does the same for state tax purposes. Trump’s state returns also will reveal how much he pays in taxes not only to New York state, but also to New York City—which itself will spend somewhere in the range of $60 million a year protecting the Trump family during his presidency.
"And if New York wants to publish President Trump’s state tax returns, it can. On April 26, State Assemblyman David Buchwald and State Senator Brad Hoylman introduced legislation to release state tax returns filed by the president and certain other elected officials. Specifically, the law would require the state tax authority to post on its website the last five years of returns filed by the president and vice president, the state’s two U.S. senators, as well as the governor, lieutenant governor, state comptroller and state attorney general. The state tax authority would continue to post returns filed by those individuals until they leave office. (Of course, if the president or vice president does not file New York returns, the state tax authority wouldn’t have to post anything from those officials.)"
There's more and you can read it here:
http://www.politico.com/magazine/story/2017/05/02/how-new-york-release-donald-trump-tax-returns-215094
"The idea is a simple one: Each year, Trump files federal income tax returns with the IRS and a similar resident income tax return with New York. The state form doesn’t include all the same information as Trump’s federal filings, but it includes much of it. Trump’s state returns disclose how much income he earns from in-state and out-of-state sources and what deductions he claims for charitable contributions and various other expenses. If Trump uses phantom losses to zero out his federal income tax liability, he almost certainly does the same for state tax purposes. Trump’s state returns also will reveal how much he pays in taxes not only to New York state, but also to New York City—which itself will spend somewhere in the range of $60 million a year protecting the Trump family during his presidency.
"And if New York wants to publish President Trump’s state tax returns, it can. On April 26, State Assemblyman David Buchwald and State Senator Brad Hoylman introduced legislation to release state tax returns filed by the president and certain other elected officials. Specifically, the law would require the state tax authority to post on its website the last five years of returns filed by the president and vice president, the state’s two U.S. senators, as well as the governor, lieutenant governor, state comptroller and state attorney general. The state tax authority would continue to post returns filed by those individuals until they leave office. (Of course, if the president or vice president does not file New York returns, the state tax authority wouldn’t have to post anything from those officials.)"
There's more and you can read it here:
http://www.politico.com/magazine/story/2017/05/02/how-new-york-release-donald-trump-tax-returns-215094