No Return, No Clock: Why Unfiled Years Stay Open to IRS Assessment

I hear this more than you would think: it has been more than three years, so the IRS cannot touch that year anymore. If you never filed a return for that year, that is wrong. The three-year assessment statute runs from the date a return is filed. No return, no start date. No start date, no end date.

This guide explains the statute that keeps unfiled years open, why a return the IRS prepares for you does not fix the problem, and how filing your own return changes the math. It is about the deadline rules, not about how many years you should file; those decisions belong in a broader conversation about your situation.

What the statute says

Section 6501(c)(3) of the Internal Revenue Code is one sentence: in the case of failure to file a return, the tax may be assessed, or a proceeding in court for the collection of such tax may be begun without assessment, at any time.

At any time means exactly that. There is no outside limit while the return remains unfiled. The IRS can assess a 2015 liability in 2035 if no 2015 return was ever filed, subject to its own internal policies on how far back it chooses to go. Policies can change. The statute is what limits the IRS, and for unfiled years the statute does not.

A substitute for return does not start the clock

When you do not file, the IRS may prepare a return for you. Section 6020(b) of the Code authorizes the IRS to make a return from its own knowledge and from information it can obtain when a person fails to file. These are often called substitutes for return or SFRs. The IRS typically builds them from the W-2s and 1099s reported under your Social Security number, with none of the deductions or credits you might have claimed.

Here is the part most people miss. Section 6501(b)(3) says that notwithstanding section 6020(b), the execution of a return by the Secretary under that authority shall not start the running of the period of limitations on assessment and collection. An IRS-prepared return does not count as your return for statute purposes.

So the IRS can prepare a substitute, assess tax from it through the deficiency process, and the assessment period for that year remains open. If the IRS later finds more income, it can assess again. The year stays open until you file.

What the IRS does with an SFR assessment

The SFR process still has to go through deficiency procedures. The IRS mails a notice of deficiency, you have the period set by IRC 6213(a) to petition the Tax Court, and if you do nothing the tax is assessed. The guide to how a notice of deficiency affects the statute explains that process.

Once that assessment posts, a separate clock starts: the ten-year collection statute under IRC 6502. IRM 5.1.19.3.15 confirms that upon a deficiency assessment based on a section 6020(b) return, the ten-year period on collection begins. That means an unfiled year can have a running collection clock on the SFR assessment while the assessment clock for that year never started.

The same IRM section explains what happens when you later file your own original return. If your return shows less tax than the SFR assessment and the IRS accepts it, the IRS should abate the difference, and the original collection expiration date stays in place. If your return shows more tax, the IRS assesses the increase, and that new assessment gets its own collection date.

Filing your own return starts the clock

Section 6501(c)(3) talks about failure to file a return. Once a valid return is filed, that exception stops applying, and the normal rule takes over. Section 6501(a) runs three years from the date the return was filed, whether or not it was filed on time.

The Supreme Court described this point in Badaracco v. Commissioner, 464 U.S. 386 (1984). In distinguishing the no-return rule from the fraud rule, the Court said it is settled that section 6501(c)(3) ceases to apply once a return has been filed for a particular year, regardless of whether that return is filed late. The Court said the provision literally becomes inapplicable once a return has been filed.

That gives a non-filer real control over the assessment clock. A late return filed today starts a three-year assessment period today, assuming no other exception applies. Until it is filed, the period never starts.

The return has to be a real return

Filing something is not the same as filing a return. The IRS applies the valid return criteria in IRM 25.6.1.6.14: enough data to calculate the tax, a document that purports to be a return, an honest and reasonable attempt to comply, and a signature under penalties of perjury. That same provision says an unsigned return does not start the assessment statute.

Protest documents, zero returns built on frivolous theories and unsigned forms do not get you a start date. Neither does a return sent somewhere other than where the IRS directs it to be filed. The guide to the three-year statute covers the filing rules in more detail.

Unfiled years and refunds are a different story

The assessment clock and the refund clock are not mirror images. While the IRS has unlimited time to assess an unfiled year, your time to claim a refund for that year is limited by IRC 6511. An original return can serve as the refund claim, but the amount you can recover depends on when the tax was paid and when the return is filed.

That is why people who are owed money for old years lose it. Withholding is treated as paid on the return due date for refund purposes under IRC 6513(b)(1). Wait too long and the lookback period no longer reaches it. The details are in the guide to late returns that claim refunds.

Strategy for an unfiled year

Knowing that the year is open changes the decisions. Waiting does not run out the IRS clock on assessment. It only runs out your clock on refunds, while penalties and interest keep building on any balance.

Filing your own accurate return usually puts you in a better position than living with an SFR. You get to claim the deductions, filing status and credits you are entitled to. You start the three-year assessment clock. And you take the year out of the any-time category.

There is one more category to keep separate. If the failure to file was part of a fraudulent scheme, other exceptions and other exposure may apply, and the planning is different. That analysis belongs with a lawyer before anything is filed.

For the broader decisions that come before filing, the library article on delinquent return strategy is a good companion to this one.

The bottom line

No return means no assessment deadline under IRC 6501(c)(3). An IRS substitute for return does not change that, because IRC 6501(b)(3) says it does not start the clock. A valid return that you file, even years late, does start it.

If you are waiting for an unfiled year to expire, you are waiting for something that is not going to happen. The clock starts when you file.

One last practical note. Before you file anything for an old year, pull your wage and income transcript so the return reflects every information return the IRS already has. A return that leaves out a reported item invites the very adjustment you are trying to avoid, and it can turn a clean start date into a new dispute about omitted income.