If you received a CP59 and didn't respond, the CP515 is the IRS's second notice. If you ignored that too, the CP518 is the final warning. After the CP518, the IRS files a Substitute for Return and assesses the tax without your input.
CP515: Second Notice
The CP515 repeats the message from the CP59 with increased urgency. The IRS still doesn't have a record of your return and they're giving you another chance to file. The notice identifies the tax year in question and may show the income information the IRS has received from third parties.
If you filed the return but the IRS doesn't have it, send a copy to the address on the CP515 with proof of original filing. If you weren't required to file, respond explaining why (income below the filing threshold, for example) and include documentation.
CP518: Final Notice
The CP518 is the last stop before enforcement. The language is direct: file your return now or the IRS will prepare a Substitute for Return based on the income information they have. The SFR will use single filing status, the standard deduction, no credits, no dependents, and no business expenses. The resulting assessment will almost certainly be higher than what you actually owe.
After the CP518, the next piece of correspondence you'll receive is the CP2566, which is the SFR proposed assessment with a 30-day deadline to accept or file your own return.
Why You Need to File Now
Every day you wait adds to the failure-to-file penalty (5% per month, up to 25%) and the failure-to-pay penalty (0.5% per month). Interest compounds daily. A tax bill that would have been $5,000 with a timely return could be $8,000 or more after years of penalties and interest.
More importantly, you might be owed a refund. If your employer withheld taxes and your actual liability is less than the withholding, you have money coming back. But the refund statute gives you only three years from the original due date to claim it. After that, the refund is gone forever. If you're getting CP515 or CP518 notices for tax years more than two years old, you're approaching that cliff.
Multiple Unfiled Years
If you have multiple years of unfiled returns, the IRS generally requires the last six years to be filed before they'll work with you on resolution. Start with the most recent year and work backward. Get current first, then address the older years.
If you're getting non-filer notices, call us at (813) 229-7100. We file delinquent returns every week and can help you get caught up.