Assessment Transaction Codes

Assessment codes establish or adjust the tax liability on a module. When these post, they create the legal basis for IRS collection.

Core Assessment Family

TC 150 ──> Original Return Assessment
TC 290 ──> Additional Tax Assessment / Adjustment
TC 300 ──> Examination Deficiency Assessment
TC 301 ──> Abatement of Examination Deficiency

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TC 150: Original Return Posted

• Function: Establishes the initial return and assesses the tax liability reported by the taxpayer on their original Form 1040.
• Key Details:
  • Sets the original ASED (Assessment Statute Expiration Date).
  • Contains cycle date and Julian date showing when and where the return was received and processed.
  • If $0.00, taxpayer reported zero tax liability.
• Related Transactions: Often immediately followed or paired with TC 806 (withholding) or refundable credits (like TC 768 EITC).

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TC 290: Additional Tax / Adjustment

• Function: Used to assess additional tax or post general module adjustments.
• Amount Significance:
  • Positive Dollar Amount (+$500.00): Taxpayer owes additional tax or an adjustment was processed increasing liability.
  • Zero Dollar Amount ($0.00): Frequently used by IRS tax examiners and automated systems to release holds, apply interest/penalty computations, or note module actions without changing base tax.
  • Negative Dollar Amount (-$300.00): Abatement / reduction of previous assessment.

TC 290 vs TC 300

TC 290 is a general additional tax assessment or adjustment code. TC 300 is specifically used for an Examination tax deficiency following an audit or correspondence review.

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TC 300 & TC 301: Examination Assessment & Abatement

TC 300: Examination Deficiency Assessment

• Posts an audit/exam determination increasing the taxpayer's tax.
• Follows formal IRS exam procedures (notices of deficiency, CP2000 underreporter matching, or field/office audits).
• Directly impacts the CSED clock for the newly assessed amount.

TC 301: Abatement of TC 300

• Decreases or eliminates a previously assessed TC 300 exam deficiency.
• Memory hook:

  300 adds exam tax; 301 abates it!