IRS Letter 525 is issued to inform the taxpayer of proposed changes stemming from an IRS examination. The letter explains the changes to the tax return and requests payment of the balance due (or outlines the amount of the adjusted refund).
This must be done within 30 days of the notice date. If not, you will lose your right to appeal the IRS’s decision. Be sure to attach documentation supporting your claim. Include your phone number (with the area code) and the best time of day to call. Be sure to write your last name, SSN, and the tax year on each page you’re attaching to the response. Before mailing your response to the IRS, make a copy of the entire correspondence for your records. If possible, it is suggested you send the response through Certified Mail with Return Receipt requested. The IRS will then review the information and either reverse the proposed changes or forward your case for audit.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.