All organizations recognized as tax-exempt under Internal Revenue Code section 501(c)(3) are required to file Form 990. This includes private foundations and other charities, such as churches, educational institutions, and other non-profit organizations. Generally, these organizations must file their Form 990 annually by the 15th day of the 5th month after the end of their tax year. For example, a calendar year filer would submit their Form 990 by May 15th.