ADC 990 is an accounting term used in the United States for the Form 990, which is an annual information return that nonprofit organizations file with the Internal Revenue Service (IRS). The form provides detailed financial and organizational reporting on the activities and operations of tax-exempt organizations. It helps to ensure transparency and accountability for these organizations while assuring the public that they are using their resources effectively and efficiently. The data from these forms is also used by the IRS to determine whether the organization continues to qualify for its tax-exempt status. In short, ADC 990 refers to the filing obligation for nonprofit organizations in the USA.