IRS Master File Transaction Codes — Complete Reference

Transaction codes (TCs) are the three-digit entries that drive every IRS Master File account. When you pull an account transcript or record of account, each posting is tagged with a TC that tells the Master File what the entry is: a return, an assessment, a payment, a penalty, an examination flag, a notice, a statute hold. Reading TCs correctly is the difference between knowing your client's case is in active levy status and thinking everything is fine.

This page is the reference we use ourselves. Every entry below is sourced from the IRS's own public documentation — primarily Document 6209's Master File Codes section. Codes we aren't fully confident about are omitted rather than guessed.

TC	Short description	Detailed meaning	Common tax-pro implications
000–099 · Entity changes
000	Establish an Account	Adds a new taxpayer account / entity module to the Master File (BMF or IMF). Posts the filing requirements and name/address.	First posting on any new entity. Expect this before any return shows up.
011	Change EIN or SSN	Changes the Taxpayer Identification Number on the account. Account is consolidated or re-linked under the new TIN.	TIN mismatches often surface here — watch for mis-posted modules before/after the change.
012	Reopen Account	Reopens a previously closed entity module.	Signals the entity was closed (e.g., 020) and has been reactivated.
013	Name Change	Changes the primary name on the entity. For businesses, reflects legal name change; for individuals, name correction.	Confirm the client's current legal name matches IRS records before filing POA or correspondence.
014	Address Change	Updates the address of record on the Master File entity.	Critical — CP/LT notices go to the address on file. If levy notices went to an old address, this date matters for CDP timeliness arguments.
016	Miscellaneous Entity Change	Updates other entity data (filing requirements, fiscal year month, location codes, sort name).	Often accompanies a filing requirement change or POA address update.
017	Spouse SSN Change	Adds or changes the secondary (spouse) SSN on a joint IMF account.	Check when filing status analysis or innocent-spouse issues are in play.
020	Close Account / Delete Entity	Closes the entity module. No further returns expected.	For businesses, typically final 941 or dissolution. Confirm FTD/941 filing requirement is actually zero before relying on this.
030	Update Location Code	Updates the district office / area office code controlling the account.	Relevant when figuring out which IRS campus/ACS office your case routes to.
040	Directs Change to Valid SSN	Directs account processing under a validated SSN (used when the IRS previously had an invalid/temporary TIN).	Often appears for clients who had ITIN/SSN conversion issues.
041	Directs Change to Invalid SSN	Reverses TC 040; processes account under invalid-SSN segment.	Indicates an SSN validation problem still outstanding.
050	Update Location Codes After Merge	Adjusts location codes following an entity merge or TIN consolidation.	Housekeeping — usually no action required.
053	Plan Year Ending Month Change	Changes the plan/fiscal year ending month for BMF entities.	Impacts which tax year modules you expect to see. Check before requesting transcripts.
054	Retained FYM	Retains fiscal year-ending month when a prior change would have altered it.	Informational.
100–199 · Returns & initial assessments
140	IRS Inquiry Re: Delinquent Return	IRS has identified a missing required return and opened an inquiry module.	Precursor to CP 59/515/516 and eventually SFR assessment if not resolved.
150	Return Filed & Tax Liability Assessed	Original return posted and the liability self-reported on the return is assessed.	Critical. Starts the Assessment Statute Expiration Date (ASED, 3 years) and is the baseline for the 10-year CSED once a balance exists. TC 150 date = return filed/processed date.
151	Reversal of TC 150	Reverses an erroneously posted return.	Rare — usually a mis-posted return being backed out.
152	Entity Update by TC 150	Internal update generated when a return posts and changes entity data.	Informational.
160	Manual FTF Penalty Assessment	Manually assessed Failure to File penalty (IRC 6651(a)(1)).	First-Time Abatement (FTA) candidate if clean compliance history. Verify whether assessed with TC 160 (manual) vs 166 (systemic).
161	Abate FTF Penalty (TC 160)	Reverses or abates a manually-assessed FTF penalty.	Confirms a prior abatement request was granted.
162	Removed FTF Penalty	Removes a failure-to-file penalty previously posted.	Informational abatement record.
166	Delinquency Penalty (Systemic)	System-generated Failure to File penalty, computed at posting of a delinquent TC 150.	Most FTF penalties are 166, not 160. Abatement math: compare 166 amount + 270 amount for combined FTF+FTP relief.
167	Abate Delinquency Penalty	Reverses TC 166.	Confirmation FTA or reasonable cause relief posted.
170	Estimated Tax Penalty (Manual)	Manually-assessed estimated tax penalty (IRC 6654 / 6655).	Not abatable under FTA. Reasonable cause is narrow — check waiver rules (retirement, disability, casualty).
171	Abate Estimated Tax Penalty	Reverses TC 170.	Informational.
176	Estimated Tax Penalty (Systemic)	System-computed estimated tax penalty at return posting.	Standard companion to most 150s with underwithholding.
177	Abate Estimated Tax Penalty (176)	Reverses TC 176.	Informational.
180	FTD Penalty (Manual)	Manually-assessed Failure to Deposit penalty for 941/940 employment taxes (IRC 6656).	Common on late payroll deposits. FTA may apply for the earliest period.
181	Abate FTD Penalty	Reverses TC 180.	Informational.
186	FTD Penalty (Systemic)	System-computed FTD penalty.	Standard on delinquent 941 deposits.
187	Abate FTD Penalty (186)	Reverses TC 186.	Informational.
196	Interest Assessed (Systemic)	System-computed interest assessment.	Appears at most assessments, notices, and period-close events.
197	Abate Interest Assessed	Reverses TC 196.	Usually follows penalty abatement (interest on the abated penalty drops off).
200–299 · Transfers, penalties, additional assessments
200	Taxpayer Identification Number Penalty	Penalty for failure to provide a valid TIN on an information return.	BMF information-reporting penalty. Review against backup-withholding letters.
234	Daily Delinquency Penalty	Daily accruing penalty (e.g., Form 5500/990).	Exempt-org / plan-filing territory; can balloon quickly.
235	Abate TC 234 Penalty	Reverses the daily delinquency penalty.	Informational.
238	Daily Delinquency Penalty (Systemic)	System-generated variant of TC 234.	Same implications as 234.
239	Abate TC 238 Penalty	Reverses the systemic daily delinquency penalty.	Informational.
240	Miscellaneous Penalty (Manual)	Catch-all bucket for assessed civil penalties not covered by other codes.	Look at the civil-penalty reference number (the MFT 55 assessment) for what this actually is — TFRP, ACA employer shared responsibility, preparer penalty, etc.
241	Abate Miscellaneous Penalty	Reverses TC 240.	Informational.
246	Form 8752 Penalty / 1065 Penalty	Penalty for late partnership/S-corp return or Form 8752.	Partnership late-filing penalty — Rev. Proc. 84-35 relief may apply for small partnerships.
247	Abate TC 246	Reverses the partnership penalty.	Informational.
270	Failure to Pay Penalty (Manual)	Manually-assessed FTP penalty (IRC 6651(a)(2)/(3)).	Accrues at 0.5%/month (1% after final notice). FTA eligible. Pair with TC 160/166 analysis for total penalty relief.
271	Abate FTP Penalty	Reverses TC 270.	Confirms FTP abatement (often part of FTA package).
272	FTP Penalty on Proposed Assessment	Recomputed/adjusted FTP penalty tied to an examination or audit reconsideration.	Often seen with 300/290 activity.
276	FTP Penalty (Systemic)	System-computed FTP penalty, accruing month by month on balance-due periods.	Running total penalty — will continue to accrue until balance paid or period in CNC/OIC/IA.
280	Bad Check Penalty	Penalty for a dishonored payment (IRC 6657).	2% of the payment amount (or flat minimum on small payments).
286	Bad Check Penalty Reversed	Reverses TC 280.	Informational.
290	Additional Tax Assessment	Additional tax assessed after TC 150 — from AUR/CP2000, math-error, amended return, or manual adjustment.	Critical. Each TC 290 that increases tax resets the 10-year CSED for that assessment amount. Look at the assessment date — not the tax year — to compute CSED. Common after CP 2000 closes.
291	Abatement of Prior Tax Assessment	Reduces a prior assessment (reverses all or part of a 150/290/300).	Audit reconsideration win, amended return reduction, or IRS correction.
294	Additional Tax Assessment w/ Interest Date	Same as 290 but with a specified interest computation date.	Used when the assessment relates to an earlier period for interest purposes.
295	Abatement w/ Interest Date	Reverses 294.	Informational.
298	Additional Tax Assessment (Manual)	Manually-input additional assessment, often with specific interest/penalty handling.	Treat like TC 290 for CSED purposes.
299	Abatement (Manual)	Reverses TC 298.	Informational.
300–399 · Examination
300	Additional Tax by Examination	Additional tax assessed as a result of an IRS examination.	Critical. Audit deficiency. Starts a new 10-year CSED from the 300 date. Often paired with TC 420/421.
301	Abatement of Exam Assessment	Reverses TC 300 — audit reconsideration, Appeals, or Tax Court win.	Confirms an audit defense succeeded.
304	Additional Tax by Exam (Restricted Interest)	Exam assessment with restricted interest computation.	Similar to 300 with special interest treatment.
305	Abatement of 304	Reverses TC 304.	Informational.
308	Additional Tax by Exam (Manual)	Manual exam assessment variant.	Treat like TC 300.
309	Abatement of 308	Reverses TC 308.	Informational.
320	Fraud Penalty	Civil fraud penalty (IRC 6663) — 75% of the underpayment attributable to fraud.	Serious. Not abatable under FTA. Often paired with exam assessment. Consider appeals strategy carefully.
321	Abatement of Fraud Penalty	Reverses TC 320.	Informational.
336	Interest Assessment (Exam)	Interest posted in connection with exam adjustments.	Companion to 300/308.
340	Restricted Interest Assessment	Interest assessed with restricted computation.	Often seen on carryback/carryforward adjustments.
341	Abatement of Restricted Interest	Reverses TC 340.	Informational.
342	Interest Adjustment (Manual)	Manually-adjusted interest amount.	Review the date for CSED purposes.
350	Negligence Penalty	Accuracy-related / negligence penalty (IRC 6662) — 20% of the underpayment.	Frequent AUR/CP2000 companion. Reasonable cause defense available; not FTA eligible.
360	Fees/Collection Costs	Lien filing fees, collection costs, court costs.	Small amounts but they affect payoff calculations.
370	Account Transfer-In	Balances transferred into this module from another.	Follow the account-transfer chain if payoff looks off.
380	Overpayment Cleared Manually	Credit balance cleared from the module manually.	Check whether offset (TC 826) or refund (TC 846) posted instead.
400–499 · Account transfers, examination indicators, freezes
400	Account Transfer-Out	Module transferred out to another account/TIN.	Balance moved. Pair with the destination account's TC 370.
401	Account Transfer-In (Reversal)	Reverses an inbound account transfer.	Informational.
402	Account Transfer-Out Reversal	Reverses an outbound account transfer.	Informational.
420	Examination Indicator	Module selected for examination / opened for audit.	Critical. Audit is open. Tread carefully — amended returns, payments, and contact strategy all change once a 420 posts. Paired with TC 424 when case is assigned.
421	Closed Examination / Reverse TC 420	Examination closed. No additional assessment, or assessment complete.	Audit over. Check for companion TC 300/301 to see outcome.
424	Examination Request Indicator	Case being built for audit — DIF score hit, correspondence exam, or referral.	Often appears before TC 420. Audit is imminent.
425	Reverse TC 424	Exam request cancelled.	No audit — return de-selected.
428	Examination or Appeals Case Transfer	Case transferred between exam groups or to Appeals.	Expect a new revenue agent / appeals officer contact.
429	Reverse TC 428	Reverses transfer.	Informational.
470	Taxpayer Claim Pending	Freezes the module for a pending taxpayer claim (amended return, abatement request, offset bypass).	Refunds/offsets held. With closing code 94 this is an OIC processability freeze.
471	Reversal of TC 470	Releases the claim-pending freeze.	Claim resolved one way or the other.
472	Claim Pending (Variant)	Secondary claim-pending freeze variant.	Same implications as 470.
474	Interrupts Normal Assessment	Short-duration hold on assessment processing.	Informational — temporary.
475	Reverses TC 474	Releases the hold.	Informational.
480	Offer in Compromise Pending	OIC has been submitted and is pending IRS review.	Critical. CSED is tolled during OIC consideration (+30 days). Collection is suspended. Refunds during the year of acceptance are offset.
481	Offer in Compromise Rejected	OIC rejected by IRS.	Taxpayer has 30 days to request Appeals.
482	Offer in Compromise Withdrawn	Taxpayer withdrew the OIC.	Releases the 480 freeze. Collection resumes.
483	OIC Returned	OIC returned as non-processable (missing info, not in compliance, etc.).	Does not toll CSED. Fix the defect and refile.
488	Installment / Manual Billing	Manual billing control on an installment arrangement.	Usually seen on partial-pay / manual IAs.
489	Installment Defaulted	Installment agreement defaulted.	CP 523 follows. Taxpayer has appeal rights within 30 days.
500–599 · Collection status & freezes
500	Military Deferment	Combat-zone or military deferment — collection and filing obligations suspended.	Statutes tolled. Confirm entry/exit dates.
510	Release of TC 500	Ends military deferment.	Statutes resume.
520	Pending Litigation / CDP / Bankruptcy Freeze	Module frozen for bankruptcy, CDP hearing, litigation, Innocent Spouse claim, or other statutory event. The closing code identifies which.	Critical. CSED is tolled. Closing codes include 60–67 (bankruptcy), 70s (CDP hearings), 80s (litigation), 84 (Innocent Spouse), 85 (Innocent Spouse claim). Always note the closing code and date.
521	Release of TC 520	Bankruptcy/CDP/litigation freeze released.	CSED resumes. Recompute CSED extension based on 520→521 span plus statutory add-on.
522	Correction of TC 520	Correction to prior 520 posting (wrong closing code, date correction).	Update your CSED worksheet.
524	Collection Hold / Undelivered Mail	Holds collection activity — mail undelivered, address unknown.	Client is likely out of contact with IRS. Confirm address and respond.
525	Reverses TC 524	Releases the mail-undelivered hold.	Informational.
530	Currently Not Collectible	Account placed in Currently Not Collectible status — typically hardship (closing code 24, 25, 28, 32).	Critical. Active collection stops. CSED continues to run. IRS reviews at income thresholds. Closing code tells you why (24/25/32 = hardship; 03 = unable to locate; 12 = unable to contact).
531	Reversal of TC 530	CNC status reversed — collection resumed.	IRS's income review triggered reinstatement. Check for TC 971 AC 043/044 as the reason.
534	Expired Balance Write-Off	Balance written off — usually CSED expiration.	Critical. CSED has expired. Debt is legally uncollectible. Confirm the periods match your CSED worksheet.
537	Suspended from Collection	Case suspended — multiple possible reasons (systemic).	Review surrounding codes for context.
540	Deceased Taxpayer	Indicates primary taxpayer is deceased.	Estate handling required. TC 540 + 530 CC 08 often posts for death.
550	Waiver Extension of CSED	Taxpayer agreed to extend CSED (Form 900 or similar).	Rare post-RRA98 but still seen. Pull the waiver document.
560	Waiver Extension of ASED	Assessment statute extended by consent (Form 872 / 872-A).	Normal during long-running exams. Verify expiration date.
570	Additional Liability Pending / Credit Hold	Freezes refund or credit on the module pending review or additional assessment.	Very common. Refund frozen. Causes include AUR, identity verification, math-error review, exam build-up. Resolved by TC 571 or 572, often paired with 290/420.
571	Reverse TC 570	Releases the credit/refund freeze.	Refund typically issues (TC 846) within one to three cycles after 571.
572	Correction of TC 570	Corrects a prior 570 posting.	Informational.
576	Unallowable Tax Hold	Holds a credit for additional review (unallowable deductions/credits flagged).	Similar to 570 but specifically credit-review flavored.
577	Reverses TC 576	Releases 576 hold.	Informational.
582	Lien Indicator	Federal tax lien filed (Notice of Federal Tax Lien).	Critical. NFTL is on public record. CDP rights triggered (Form 12153, 30-day window from CP 504 / Letter 3172). Lien withdrawal and subordination analysis belongs here.
583	Reverse Lien Indicator / Lien Release	NFTL released or withdrawn.	Within 30 days of full-pay or when balance is otherwise satisfied.
590	Satisfying Trans — No Return Secured	Closes a delinquent-return module without the return being filed — not liable, little/no tax impact, or other closing reason.	Closing code matters: 20 = no liability, 75 = referred to exam, etc.
591	No Longer Liable for Filing	Taxpayer no longer required to file that return type.	Confirms a filing-requirement change was processed.
592	Reverses Unresolved Closure	Reverses an unresolved 59x closure.	Module put back into delinquent status.
593	Unable to Locate Taxpayer	IRS unable to locate TP for delinquent return inquiry.	Companion to 530 CC 03 scenarios.
594	Return Previously Filed	TP has already filed the return; module closure reflects that.	Check MFT/period to confirm.
595	Referred to Exam	Delinquent return case referred to examination for SFR.	SFR may follow. Consider filing an original return before SFR processing.
596	Referred to CI	Referred to Criminal Investigation.	Critical. Bring a criminal tax attorney in immediately.
597	Return Surveyed / Closed w/o Contact	Delinquent-return case closed without TP contact.	Informational.
598	Referred to Exam w/o Return Secured	SFR referral.	Expect TC 150 with SFR indicator and a substitute assessment.
599	Return Secured / Filed by TP	Delinquent return has been filed.	Closes the 59x delinquency.
600–699 · Payments, credits, adjustments
604	Assessed Balance Written Off	Write-off of assessed balance (rare outside CSED / no-asset scenarios).	Similar to 534 but variant-specific.
605	Reverse TC 604	Reverses the write-off.	Informational.
606	Under-tolerance Write-Off	Small-balance write-off under IRS tolerance (usually <$5).	Informational — not a strategy, just housekeeping.
608	Statute Expiration — Credit Barred	Refund statute expired (RSED) — credit can no longer be refunded.	Credit forfeited. Check 3-year/2-year RSED rules.
610	Payment w/ Return	Payment submitted with the original return (Form 1040 balance due, 941 payment, etc.).	Should match TC 150 timing.
611	Reverse TC 610 (Dishonored)	Payment-with-return reversed (usually NSF / dishonored).	Triggers TC 280 bad-check penalty.
612	Correction of TC 610	Correction of payment-with-return.	Informational.
620	Estimated Tax Payment	Form 1040-ES estimated tax payment posted.	Appears on the prepaid-credit side of the module.
621	Reverse Estimated Tax Payment	Reverses TC 620 (NSF or misapplied).	Check for payment-trace / TC 570 follow-up.
622	Correction of Estimated Payment	Correction of TC 620.	Informational.
630	Manual Application of Credit	Credit manually applied from another period/account.	Trace the origin module — often misapplied payments.
632	Reversal of TC 630	Reverses manual credit application.	Informational.
636	Separate Appropriation Refundable Credit	Specific refundable-credit posting.	Informational.
637	Reversal of TC 636	Reverses separate-appropriation credit.	Informational.
640	Advance Payment of Deficiency	Payment submitted toward a proposed deficiency (before assessment).	Often during an open audit — stops interest accrual on the paid portion.
641	Reverse Advance Payment	Reverses TC 640.	Informational.
642	Correction of TC 640	Correction of advance deficiency payment.	Informational.
650	FTD Payment (Federal Tax Deposit)	Employer FTD payment applied.	941/940 deposit posting.
651	Reverse TC 650	Reverses an FTD.	Informational.
652	Correction of TC 650	Correction of FTD.	Informational.
660	Estimated Tax Payment (Alternative)	Secondary ES payment code.	Same implications as 620.
661	Reverse TC 660	Reverses 660.	Informational.
662	Correction of TC 660	Correction of 660.	Informational.
670	Subsequent Payment	Payment posted after the original return — typically a post-notice payment or IA installment.	Very common. The workhorse payment code on collection modules. Each 670 reduces the running balance. Date = payment received date.
671	Reverse TC 670 (Dishonored)	Subsequent payment reversed (NSF).	TC 280 bad-check penalty follows.
672	Correction of TC 670	Correction of subsequent payment.	Informational.
673	Installment Agreement Payment	Payment specifically tagged as an IA installment.	Look for continuity month-over-month; gaps signal default risk.
678	Credit for Treasury Offset Program	TOP-related credit.	Informational.
679	Reverse TC 678	Reverses 678.	Informational.
680	Designated Payment — Interest	Designated payment applied specifically to interest.	Use on payoff strategy — especially OIC prep, where penalty allocation matters.
681	Reverse TC 680	Reverses designated interest payment.	Informational.
682	Correction of TC 680	Correction of designated interest payment.	Informational.
690	Designated Payment — Penalty	Designated payment applied to penalty.	Coordinate with FTA strategy so you don't pay down abatable penalties first.
691	Reverse TC 690	Reverses designated penalty payment.	Informational.
692	Correction of TC 690	Correction of designated penalty payment.	Informational.
694	Designated Payment — TFRP	Payment designated to Trust Fund Recovery Penalty.	Critical in TFRP cases — clients often want the trust-fund portion paid first.
695	Reverse TC 694	Reverses TFRP designated payment.	Informational.
700–799 · Credits, offsets, interest & statute events
700	Credit Applied	Credit transferred/applied from another source.	Trace the source.
706	Credit Transferred In	Overpayment credit received from another module.	Pair with the source module's TC 826 offset.
710	Overpayment Credit Applied from Prior Year	Prior-year overpayment elected-credit applied to current-year estimated tax.	Match to the prior-year TC 836.
712	Reverse TC 710	Reverses the prior-year credit application.	Informational.
716	Credit Elect / Generated	Generated credit elect applied forward.	Informational.
736	Interest on Overpayment	Interest paid to the taxpayer on a refund.	Informational.
740	Undelivered Refund Check	Refund check was returned as undeliverable.	Update address, request re-issue.
742	Correction of TC 740	Correction of undelivered-refund posting.	Informational.
756	Interest Paid on Refund (Credit)	Refund interest paid as a credit (not cash).	Informational.
760	Substantiated Credit Allowance	Credit allowed after substantiation (e.g., withholding verified).	Often after 570/971 review.
762	Reverse TC 760	Reverses substantiated credit.	Informational.
764	EIC Allowed (Systemic)	Earned Income Credit allowed by systemic processing.	Paired with original return processing.
765	EIC Reversal	Reverses EIC previously allowed.	Usually AUR/exam disallowance of EIC — watch for 2-year/10-year ban under IRC 32(k).
766	Credit to Account	Generic credit posting — refundable credits, carrybacks, manual credits.	Very common. Refundable credits (AOTC, ACTC), math-error corrections, and carrybacks land here. Look at the date and amount to tie it back to the cause.
767	Reverse TC 766	Reverses a TC 766 credit.	Often from AUR disallowance.
768	Earned Income Credit	EIC posted to the account.	Common. TC 768 = EIC amount claimed and allowed on the return.
769	Reverse TC 768	EIC reversed.	AUR/exam disallowance — check for IRC 32(k) ban.
770	Interest Credit on Overpayment	Interest credited to taxpayer on an overpayment.	Informational.
771	Reverse TC 770	Reverses interest credit.	Informational.
772	Correction of TC 770	Correction of interest-credit posting.	Informational.
776	Interest Allowed on Overpayment	Overpayment interest allowance.	Informational.
777	Reverse TC 776	Reverses allowed overpayment interest.	Informational.
780	Master File Account Compromised	OIC-Doubt-as-to-Collectibility accepted and recorded.	Critical. OIC has been accepted. Confirm the compromised amount and keep the taxpayer compliant for 5 years (IRM 5.8.8).
788	All Collateral Conditions of Offer Met	Collateral agreement conditions under the OIC satisfied.	Part of the OIC close-out.
790	Manual Overpayment Applied / Transferred	Manual overpayment transfer between accounts.	Trace origin and destination.
792	Credit Transferred Out	Credit moved to another module/account.	Informational — pair with TC 706 on the destination module.
796	Credit Applied from Overpaid Account	Overpayment credit applied from another account.	Informational.
800–899 · Withholding credits, offsets, refunds
800	Withholding Credit — Estate Tax	Credit for tax withheld (estate context).	Informational.
802	Credit Transferred Out — Withholding	Reverses withholding credit (transferred to another period).	Informational.
806	W-2 / 1099 Withholding	Federal income tax withholding and excess FICA credited from W-2s and 1099s attached to the return.	Very common. TC 806 is the taxpayer's withholding credit. Verify amount against W-2 totals — mismatches drive CP 2000 and refund holds (TC 570).
807	Reverse TC 806	Withholding credit reversed (W-2 mismatch, disallowed withholding).	AUR adjustment or withholding verification failure.
811	Allowance of Claim	Claim for refund allowed.	Often follows Form 843 or amended-return allowance.
820	Credit Transferred — Manual	Manual credit transfer to another module.	Trace destination.
821	Reverse TC 820	Reverses manual credit transfer.	Informational.
822	Correction of TC 820	Correction of credit-transfer posting.	Informational.
824	Credit Transferred to Non-MF Account	Credit moved to a non-Master File account (e.g., civil penalty MFT 55).	Informational — follow the destination.
826	Credit Transferred / Offset to Other Tax	Overpayment offset to another tax module's balance.	Common. TC 826 = your refund got grabbed to pay another tax year's balance. Check the cross-reference module for the destination.
830	Overpayment Credit Elect	Overpayment elected-forward to next year's estimated tax.	Paired with destination module's TC 710.
832	Reverse TC 830	Reverses credit-elect.	Informational.
836	Overpayment Credit Elect (Generated)	Systemic credit-elect posting.	Informational.
840	Manual Refund	Manually-issued refund check.	Expect explanation from the campus — often after a taxpayer-requested refund trace.
841	Refund Cancelled / Returned	Refund cancelled or check returned to Treasury.	Informational.
842	Correction of TC 840	Correction of manual refund.	Informational.
846	Refund Issued	Refund was issued to the taxpayer — date and amount shown.	Very common. TC 846 = refund actually sent. The date is the scheduled disbursement / direct-deposit date. No 846 = no refund yet.
848	Reverse TC 846	Refund reversed / recalled.	Rare — usually after a wire-out error or fraud hold.
856	Interest Paid on Manual Refund	Interest paid on a manual refund.	Informational.
876	Overpayment Credit Applied — Other Taxpayer	Overpayment applied to a related taxpayer's balance (e.g., spouse, predecessor entity).	Often innocent-spouse or joint-to-separate offset territory.
890	Applied Non-Refund to Other Period	Non-refundable overpayment applied to another module.	Informational.
896	Offset — Past-Due Non-Tax Debt	Refund offset to non-tax debt (child support, state tax, federal non-tax via TOP).	Common surprise for clients. FMS/BFS handles disputes, not IRS.
900+ · Exam freezes, POA, notices, miscellaneous
914	Active CI Investigation Freeze	Criminal Investigation has placed a -Z freeze on the account.	Critical. Active CI case. Stop all civil-side action and engage a criminal tax attorney.
916	Examination Freeze	Freezes the module during examination build-up.	Paired with 424/420 activity. Refunds/offsets held.
918	Non-Filer Freeze	Holds module pending unfiled-return investigation.	Usually paired with 59x codes.
922	AUR Review / Underreporter Review	Automated Underreporter review — potential unreported income detected via third-party matching.	Important. CP 2000 is likely coming. Get the wage & income transcript and reconcile against the filed return now, before the notice arrives.
960	Add / Update Centralized Authorization File (POA)	Form 2848 Power of Attorney (or related authorization) posted to CAF.	Critical for practitioners. TC 960 = your POA posted. You now have standing on the account. Pull the transcript again to confirm.
961	Reverse / Revoke Prior POA	Prior POA revoked or replaced.	Confirm you're now the active rep and the prior rep is removed.
962	Correct CAF Indicator	Correction to CAF posting.	Housekeeping.
971	Miscellaneous Transaction / Notice Issued	Catch-all informational marker. Most commonly used to record that an IRS notice was issued — the Action Code tells you which notice. Also used for amended-return receipt, installment-agreement requests, CDP requests, and many other events.	Read the Action Code, not just the 971. AC 199 = Information Notice sent, AC 063 = CDP rights sent (Letter 3172/CP 504), AC 601 = IA request, AC 043/044 = CNC review triggers. See the Action Code reference below.
972	Reversal of TC 971	Reverses a 971 posting.	Informational — the action tied to the 971 was undone or corrected.
973	Application for Tentative Refund	Form 1045 / Form 1139 (tentative refund claim for NOL carryback).	Informational — statute and refund considerations apply.
976	Duplicate Return Filed	A duplicate return (often an amended 1040-X or second original) posted to a module that already has a TC 150.	Common. Usually the amended return. Check for TC 290 / 291 for the resulting adjustment.
977	Amended Return Posted	Form 1040-X / 1120-X / similar amended return accepted for processing.	Look for TC 290/291 adjustments that follow. Amended-return processing is slow (often 4–6 months).
980	W-2/1099 Discrepancy Notice	Indicator for W-2/1099 matching issue.	AUR indicator — CP 2000 trail.
993	Insurance Premium Tax Credit / Other Special Credit	Specialized credit posting (context varies).	Review surrounding codes for context.

No transaction codes match that filter. Try a different keyword.

Understanding TC 971 Action Codes

TC 971 is a catch-all marker. The three-digit Action Code posted with it is what tells you why the 971 fired. You'll see these in the transcript's memo line or misc field.

A short list of the Action Codes that matter most on collection cases:

AC 043 / AC 044 — CNC reverse indicators (IRS income review pulled the client out of CNC; expect TC 531).
AC 063 — CDP rights notice sent (Letter 3172 / CP 504 companion). 30-day window to file Form 12153.
AC 069 — Pending installment agreement.
AC 120 — Amended return received.
AC 121 — Examination referral.
AC 199 — Information / miscellaneous notice (look at the cross-reference for the specific CP/LT).
AC 262 — Wage & Income Transcript mismatch flagged.
AC 601 — Installment Agreement request received / established.
AC 602 — Installment Agreement terminated.
AC 604 — CNC (unable to locate) indicator.
AC 163 / AC 164 — CP 2000 / AUR notice-stage indicators.

When a TC 971 references a specific notice (CP 504, LT 11, CP 2000, etc.) the description line usually includes the notice identifier. TRH's notice lookup picks these up automatically from the transcript description.

Where transaction codes appear

Not every transcript type shows transaction codes. If you need to see TCs, pull the right transcript:

Account Transcript

Primary source for TCs. Shows every posting to the module — assessments, payments, penalties, interest, freezes, notices, refunds. This is the transcript you read for resolution work.

Record of Account

Combines the Account Transcript with the Tax Return Transcript. Shows both the original-return line items and the full TC posting history. Useful when you need to see what was filed alongside what posted.

Tax Return Transcript

Does not show TCs. Only shows line items from the original return as filed — no assessments, payments, or adjustments. Useful for mortgage/loan verification but not for collection analysis.

Wage & Income Transcript

Third-party information returns (W-2, 1099, K-1, 1098, etc.). No TCs — but essential for reconciling against TC 806 withholding and for heading off AUR (TC 922) issues before they become CP 2000s.

Disclaimer: This reference is for educational use. Transaction code meanings and IRS systems evolve — always verify critical case decisions against current IRM guidance and the client's actual transcript. Source: IRS Document 6209, Master File Codes, public release.