I Forgot to Include a 1099 on My Tax Return, What Happens Now?
The return is filed, the refund (or payment) is settled, and then a forgotten 1099 turns up in a drawer or an inbox weeks later. It’s a common enough moment of dread, and the good news is that it’s also a fairly routine problem with a well-established fix.
The quick answer
A missed 1099 generally needs to be addressed by filing an amended return once it’s discovered, since the business or client that issued it also sends a copy to the IRS, meaning the income is already on file there even if it wasn’t included on the original return. In many cases, the IRS catches the mismatch on its own and sends a notice proposing a correction, but filing an amended return proactively is generally the more controlled way to handle it.
Why it usually doesn’t stay hidden
Payers are required to send copies of 1099 forms to both the recipient and the IRS, which means the income in question is typically already documented on the government’s side regardless of whether it made it onto the original return. The IRS runs automated matching between what’s reported on returns and what payers report separately, and a missing 1099 is one of the more common triggers for a follow-up notice. That notice, sometimes arriving months after the original filing, usually proposes an adjustment to the balance owed based on the unreported income, plus interest calculated from the original due date.
What tends to happen next
- A notice proposing changes. If the IRS catches the mismatch first, it typically sends a letter explaining the discrepancy and proposing an adjustment, along with instructions for how to respond if the recipient disagrees.
- Additional tax owed, plus interest. If the missing 1099 represents income that wasn’t otherwise accounted for, the corrected return usually results in additional tax owed, and interest accrues from the original filing deadline regardless of when the correction happens.
- Possible penalties. Depending on the amount and circumstances, there can be penalties tied to underreporting, though these can sometimes be reduced or avoided by correcting the return before the IRS sends a notice.
Filing an amendment proactively
Rather than waiting to see whether a notice arrives, many people choose to file an amended return as soon as the missing 1099 is discovered. This generally involves reporting the additional income, recalculating tax owed, and submitting the correction along with any payment due. Doing this before the IRS flags the issue independently can sometimes limit how penalties are assessed, since it demonstrates the correction wasn’t prompted by an audit or automated notice. It’s a similar principle to what generally happens when a return is filed late: acting sooner tends to limit how much interest and penalty accrue compared to waiting.
Keeping this from becoming a repeat problem
Because 1099s can arrive later than W-2s, and because gig work or freelance income sometimes generates forms from multiple platforms, it helps to keep a running list of expected forms each year, including from sources like delivery or rideshare apps. General guidance on how long to keep tax records is also useful here, since having organized records makes it far easier to spot a missing form before filing rather than after.
The takeaway
A forgotten 1099 is rarely the crisis it feels like in the moment, but it’s also not something that quietly resolves itself, since the IRS typically already has a copy of the same information. Filing an amended return once the oversight is discovered, rather than waiting to see if a notice shows up, tends to be the more manageable path and can help limit how much interest and penalty ultimately accrue.