From 1969 through 2015, presidents released their tax returns for publication. In fact, even presidential candidates released their returns. So common was the practice that some of us assumed it was the law.
According to the website, Tax Notes, “Presidents aren’t required by law to release their tax returns. Nevertheless, between 1974 and 2012, every president but Gerald Ford has made a voluntary release of the tax returns they filed while in office. Ford released no complete returns, but released 10 years of summary data including gross income, taxable income, major deductions, and taxes paid.”