What this notice is about We have important information about your child's Adoption Taxpayer Identification Number (ATIN). Your child's ATIN expires in 3 months. What you need to do Complete Form 15100, Adoption Taxpayer Identification Number (ATIN) PDF Extension Request, included with your notice if you received a Social Security number (SSN) for your child, or; Apply for a one-year extension of this ATIN by completing Form 15100, if you don't have an SSN. Detach notice stub, mail it with Form 15100 in the envelope provided. If you prefer, fax your information to the fax number in the notice using either a fax machine or an online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies. You may want to Call us at the number listed in your notice. See additional information on Adoption Taxpayer Identification Number. Frequently asked questions What can I do if I don't have a Social Security number (SSN) for my adoptive child? You can request an extension before your assigned ATIN expires by completing Form 15100 included with your notice. The extension is only valid for 1 additional year. Reference tools Publication 1, Your Rights as a Taxpayer Full list of tax forms and instructions 需要協助嗎? 您可以授權某人(英文)代表您向國稅局聯絡。 請查看您是否符合從低收入納稅人協助中心(英文)獲得協助的資格。 如果您無法在線上找到您需要的資訊,請撥打您的通知或信件上方的國稅局號碼。如果您未收到信件或通知,請使用電話協助。 如果您無法自行解決罰款,請聯絡 IRS 內部的獨立組織——納稅人權益維護服務處。