TC 150: Return Filed and Tax Liability Assessed

Every account transcript I review starts with one question: where is the TC 150? It is the anchor for everything else. Additional assessments are measured against it. Penalties are computed from it. The collection clock usually starts with it.

Here is what the code means, what it does not mean, and how to read the details around it.

The definition

IRS Document 6209 titles TC 150 "Return Filed & Tax Liability Assessed" and describes it this way: "A tax liability assessed from the original return establishes a tax module." A tax module, per the 6209 glossary, is the part of your account that reflects tax data for one type of tax and one tax period. Your 2023 Form 1040 is one module. Your 2024 Form 1040 is another.

So TC 150 does two jobs at once. It records that the IRS processed your original return, and it assesses the tax shown on that return.

That second job has a legal basis. Treasury Regulation 301.6203-1 says that, in the case of tax shown on a return by the taxpayer, the amount of the assessment "shall ... be the amount so shown." In other words, when you file a return showing tax, you have effectively told the IRS how much to assess, and the TC 150 is the assessment.

Reading the amount

The amount on the TC 150 line is the tax liability from the return as processed. It is not the balance due. Withholding, estimated payments and credits post as separate lines.

For a typical wage earner with withholding, you will see a positive TC 150 and a negative TC 806 withholding credit. If withholding exceeded the tax, the account goes to a credit balance and you will usually see a refund, TC 846, further down. If the tax exceeded withholding and payments, the account has a balance due.

If the IRS changed your figures during processing, the TC 150 reflects the corrected figure, and the return transcript will show the difference as per return versus per computer. That is covered in Tax Return Transcript vs. Record of Account.

A TC 150 for $0.00 is a special case. A return that legitimately shows zero tax posts that way. So does a dummy return created by the IRS's substitute for return program. The DLN tells you which. See Substitute for Return on Your Transcript.

Reading the date

The date next to a TC 150 is the date that matters for the collection clock. The Document 6209 glossary describes the 23C date as "the date an assessment is posted to the Master File" and "also the date the first master file notice is sent on a balance due account." IRC 6502(a) allows the IRS to collect by levy or court proceeding within 10 years after assessment.

The return received date is different. It appears in the return information section of the account transcript. It drives the failure-to-file penalty, not the collection clock. Document 6209 says TC 166, the computer-generated failure-to-file penalty, is assessed on returns posted after the due date without reasonable cause.

Keep the two dates straight. The received date tells you whether the return was late. The assessment date tells you when the tax became collectible.

What can post with or because of a TC 150

A return does not post alone. Document 6209 describes several transactions that the posting of an original return can generate.

The presence of any of these tells you something about how the return was filed. A TC 166 says the IRS considers the return late. A TC 570 says something on the return caused the IRS to hold the account. I cover holds in TC 570 and TC 571.

When the second return arrives: TC 976 and TC 977

There is only one TC 150 per module. What happens when a second return comes in for the same year?

Document 6209 says an amended return, one with condition code G or an individual 1040-X identified by block number 200 to 299, posts as TC 977: "TC 150 is replaced with TC 977 by computer." A second return that is not identified as amended posts as TC 976, a duplicate return, and on individual accounts the module is frozen from offsetting and refunding until an adjustment releases it.

Neither code changes the tax by itself. Document 6209 is explicit about TC 977: an amount posted with it "is a remittance amount and does not reflect adjustment in liability." Any change in tax comes later as a TC 290, TC 291, TC 300 or TC 301. See TC 977 and TC 976.

Condition codes that change how the return posts

Some returns carry codes that change what the computer does with them. You will not see the condition code itself on most taxpayer transcripts, but you will see its effects.

Combat zone service is the clearest example. Document 6209 says a TC 150 posted with condition code Z generates a TC 270 for zero amount, which restricts the computer's failure-to-pay penalty computation, and a TC 340 for zero amount, which restricts interest. Its freeze code table describes a combat zone indicator that "prevents offsets, suspends the ASED and CSED, and restricts interest, FTP, delinquency and estimated tax penalty" on affected modules. If you served in a combat zone and see a zero TC 270 and zero TC 340 right after your TC 150, that is the system recognizing it.

A deceased taxpayer is another. A return posted with condition code A or F can generate TC 540, which Document 6209 says records the death of the taxpayer and changes the filing requirement so blank returns are not mailed.

TC 150 on business accounts

Business modules use the same code with a few twists. Document 6209 notes that on the business master file the TC 150 assessment "may be Credit for Form CT-1, 720 and 941," which happens when the deposits and adjustments on an employment tax return exceed the liability. It also says federal tax deposits credited with TC 650 are frozen from refunding or offsetting "until TC 150 posts."

For Form 941 filers, Document 6209 describes TC 459, generated when the return posts, which records the liability of the immediately prior quarter for use in assessing the deposit penalty, and TC 970, generated when the Form 941 TC 150 posts with Schedule B data. If you are reading a payroll tax account, those lines explain why deposit penalties are computed the way they are.

What a missing TC 150 means

No TC 150, no processed original return. That can mean the return was never filed, was filed and is stuck in processing, posted to the wrong tax period or wrong taxpayer, or was rejected for some reason. Document 6209 lists TC 971 action code 001 for a TC 150 posted to an incorrect TIN or tax period. Misposted returns are real.

It also matters for the assessment statute. IRC 6501(a) generally requires assessment within 3 years after the return was filed. Under IRC 6501(c)(3), if no return is filed, the tax may be assessed at any time. And under IRC 6501(b)(3), a return the IRS prepares under its substitute for return authority in IRC 6020(b) does not start the assessment period. So the presence of your own TC 150 is not just a bookkeeping detail. It is what starts the IRS's clock to assess more.

If there is no TC 150, look at the delinquency codes. What the Transcript Shows When No Return Was Filed walks through them.

A TC 150 checklist

• Is there exactly one TC 150 for the year? If there is a TC 976 too, a second return posted.
• Does the amount match the tax on the return you filed? If not, find the processing change.
• Is the amount $0.00 on a year you never filed? Check the DLN for a substitute for return.
• What is the date? That is the assessment date to anchor the collection clock.
• What is the return received date in the header? Compare it to the due date, including any valid extension.
• Which codes posted in the same cycle? They are often generated by the return itself.

Six questions. Most transcript mysteries are answered by one of them.