If you're sure your organization qualifies for tax exempt status but haven't applied for a formal ruling, be sure it's legally taken care of before applying for your EIN. IRC 501(a) organizations are subject to automatic revocation of their tax-exempt status if they fail to file a required annual information return or notice for three consecutive years. Once you apply for an EIN, we presume your business is set up legally. The three-year period starts ticking.