The IRS has released Revenue Procedure 2026-18, its annual guidance on substitute forms — and despite the somewhat obscure name, the rules can affect virtually anyone responsible for filing or furnishing Forms 1099. What Is a Substitute Form? A substitute form is an information return produced in a format other than the official form supplied by the IRS. The IRS publishes detailed specifications governing how these forms must look and what information they must contain. For organizations that e-file their information returns with the IRS, this generally isn't something to worry about on the filing side. Whether you're filing directly through IRIS or using third-party software, the electronic filing process takes care of the IRS filing specifications. Paper filing is different. You generally cannot download Copy A of a Form 1099 from the IRS website, print it on ordinary paper, and mail it to the IRS. Paper filings must meet the IRS's specifications, which is why organizations that still file on paper typically use the special forms available from office-supply stores or other forms providers. But substitute-form rules don't stop with the IRS copy. Recipient Copies Count, Too The rules also apply to the statements furnished to recipients. That means organizations need to pay attention to the format of the Forms 1099 they provide to contractors, vendors, and other recipients — whether those statements are furnished on paper or electronically. If you prepare returns directly through IRIS and download the recipient PDF generated by the system, you're fine using that version. But in general, you can't simply put the relevant information on a piece of paper and call it a Form 1099. Recipient statements must meet IRS requirements. A Change to Address Fields Revenue Procedure 2026-18 highlights a change that has also appeared on some of the newer Forms 1099: address information is being separated into individual fields rather than appearing in one large address box. City, state, ZIP code, and other components now have their own fields. When these changes first appeared on forms such as the 2026 Forms 1099-NEC and 1099-MISC, they looked largely cosmetic. Their inclusion in the substitute-form revenue procedure suggests there may be more to the change, potentially including implications for IRIS, although the IRS has not provided enough information yet to say definitively. Welcome to the Information Return Family Revenue Procedure 2026-18 also identifies several additions to the information-return lineup: Form 1098-VLI, for reporting certain qualified passenger vehicle loan interest.Form 1099-LPS, relating to long-term care premiums paid.Form 5498-TA, relating to Trump account contributions.Form 1099-DA, for digital asset reporting. Although Form 1099-DA first came into use for 2025 reporting, the IRS continues to list it among the new forms in this revenue procedure.Meanwhile, one form has officially been put out to pasture: Form 1098-MA. The form related to the Hardest Hit Fund, Short Refinance, and Making Home Affordable programs. With funding for those programs expired, the form has been retired as well. The Takeaway If you e-file your Forms 1099 with the IRS, the substitute-form rules generally aren't something you need to think about when transmitting the returns to the government. But if you paper file with the IRS, the rules matter. And regardless of how you file with the IRS, they also matter when you furnish statements to recipients. Revenue Procedure 2026-18 gets deep into technical specifications that most organizations will never need to study line by line. But the broader lesson applies to everyone: a Form 1099 isn't simply a collection of numbers and names. The format matters, too. Listen to this week's Information Return Intelligence, powered by IOFM, for more on Revenue Procedure 2026-18 and what the substitute-form rules mean for information return filers.