Form 15105 – CP183 Guide for Form 720 Abstract Numbers

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A Form 720 gets filed in a rush with the totals correct but the per-abstract-number column left blank. The check clears and the numbers tie, yet a CP183 still arrives, because the IRS excise system cannot post the liability against any specific tax code. Form 15105 is how you supply that breakdown.

Mail the completed form within 30 days of the notice date, using the supplied envelope or the address on the original correspondence. List each tax type, the amount, and its IRS abstract number, and make sure every line reconciles to your Form 720 totals. Miss the deadline or send incomplete detail and the account can be treated as incomplete, which opens the door to penalties and interest.

Key Takeaways

• A CP183 means the IRS received your Form 720 but needs a breakdown by IRS abstract number. You must complete and return Form 15105 with the response stub, typically within 30 days of the notice date.
• Use the official one page Form 15105 PDF, revised June 2017, list each tax type, the amount, and its IRS No., then mail it using the provided window envelope.
• Every abstract number and amount must reconcile to your Form 720 totals. Validate against the current Instructions for Form 720 and Publication 510.
• If you miss the deadline or send incomplete detail, your account can be treated as incomplete, which may trigger penalties and interest.
• If you want someone to speak to the IRS for you, authorize them with Form 2848, or allow information sharing with Form 8821.

What Form 15105 is and when you must use it

Form 15105 is the IRS response form titled No Breakdown of Liability By Abstract Number on Form 720. It is a one page worksheet the IRS includes with CP183 when your filed Form 720 did not show the liability detail the IRS needs for each IRS No. It is not a stand-alone excise tax return and cannot be filed proactively or in place of Form 720. In plain terms, you list the type of excise tax, the amount, and the matching abstract number so the IRS can post your liability to the right codes.

You must complete Form 15105 if you received CP183 for a Form 720 period. The notice instructs you to fill in Form 15105, include the response stub, and mail both back so the IRS address shows through the envelope window. The notice also states the 30 day response clock and reminds you to use Form 720 Instructions and Publication 510 to confirm the correct IRS Nos.

Treat the 30 day window as a firm deadline. Answer with complete, accurate abstract level detail and you will usually stop the penalty clock.

Why this matters to you

• You keep your account accurate and current, which protects cash and avoids automated notices.
• You prevent misapplied payments that can happen when abstract numbers are missing or wrong.
• You reduce rework, because reviewers can tie each Form 15105 line to Form 720 Part I or II and to your records, using current instructions and Pub. 510.

Got a CP183, do this first

• Mark the notice date and add a response target that is at least a few days ahead of the 30 day deadline.
• Open the enclosed Form 15105 PDF, complete it, and return it with the response stub in the provided envelope so the IRS address appears in the window.
• Pull your filed Form 720, the Instructions for Form 720, and Publication 510, then validate each tax type, rate basis, and IRS No. before you write amounts on Form 15105.
• Keep copies of everything you send, including schedules and support.
• If you need representation, file Form 2848 or, for information access only, file Form 8821, both of which you can submit online.

How Form 15105 supports your Form 720

Think of Form 15105 as the bridge between your quarterly totals and the IRS posting system. Form 720 shows amounts by line, but the IRS processes those amounts using IRS Nos., the abstract numbers printed in the left and right columns of Form 720. Form 15105 lets you present liability by abstract so the IRS can match dollars to the correct account codes. That is why CP183 asks you to complete Form 15105, include the response stub, and mail within 30 days.

You will confirm each IRS No., tie your amounts to the corresponding Form 720 line, and reconcile the grand total to your filed return for that period. Use the current Instructions for Form 720 and Publication 510 as your primary references.

Simple control table you can copy

What you do	Use this source	Control to apply
Map each IRS No. to the correct tax	Publication 510	Confirm the abstract and tax description match
Tie each amount to a Form 720 line	Instructions for Form 720	Reconcile line amounts to abstract totals
Package your response	CP183 + Form 15105	Include response stub, use the window envelope

This three point checklist will keep your filing clean and auditable.

Confirm you need to respond, then gather documents

Step one, read the notice and confirm it requires a response within 30 days of the notice date (the clock starts on the date printed at the top of the IRS notice, not on the date you received it in the mail). The CP183 page spells this out and warns that penalties and interest can be assessed when accounts remain incomplete. Add your internal deadline, then assign a preparer and a reviewer.

Step two, gather the records that support each excise tax on your Form 720. This typically includes the filed Form 720, any attached schedules, calculation worksheets, invoices, fuel logs, shipment summaries, and EFTPS confirmations or proof of payment. The goal is to support every abstract number and amount you will list on Form 15105, and to balance those to the return for that quarter, including any amended filings. Use the Instructions for Form 720 for line level references.

Step three, match each tax to the correct IRS No. using current Publication 510 and the Form 720 instructions. Publication 510 explains tax categories and references “IRS Nos.” as they appear on Form 720. If anything looks off, fix it before you send the package.

Mini checklist, notice to submission

• Confirm the 30 day deadline and the periods the notice covers.
• Pull Form 720 for the same period, plus support.
• Map each tax type to its IRS No. using Pub. 510 and the Form 720 instructions.
• Enter the amounts on Form 15105. The June 2017 revision has no signature block, so no signature is required.
• Include the response stub, align the address in the window, and mail.

Reader note for firms with recurring CP183s

If your team keeps getting CP183s, the problem is almost always process, not effort. Build a light SOP that forces abstract number mapping as part of your Form 720 workflow, require structured workpapers that show rate x base, and add a pre filing reviewer checklist that confirms abstract totals tie to the return. The IRS is explicit about IRS Nos. and about using Part III correctly, so your internal documents should mirror that journey.

A tidy abstract mapping schedule solves most CP183 headaches, and it pays for itself the next busy season.

Complete Form 15105, step by step

Form 15105 is short, so precision matters. Open the IRS PDF, confirm it is the June 2017 revision, and work line by line (the June 2017 revision is still the current authorized version for tax year 2025, since the form does not depend on annual inflation adjustments). Enter your EIN, legal name, and the exact tax period on the notice. If your address changed, the form tells you how to update it by phone or online.

Enter your contact information

• EIN, legal name, tax period, and mailing address exactly as they appear on your Form 720.
• Primary and secondary phone numbers with best call times so the IRS can reach you if needed.

List liabilities by abstract number correctly

On the Tax Breakdown grid, list each excise tax type with the exact dollar amount and the IRS No. (the 2- or 3-digit Form 720 abstract code for that specific excise tax, not your EIN or any taxpayer ID). For example, fuel taxes tie to specific IRS Nos., as do communications, air transportation, and manufacturers taxes. Use Publication 510 to confirm the tax category, then use the Instructions for Form 720 to verify which IRS No. belongs to that line item. Enter amounts for the specific quarter shown on your notice.

Verify totals and the period

Re add all abstract amounts and confirm the grand total equals the total liability on your filed Form 720 for the same quarter and year. Check that each abstract belongs in that period, not another quarter. If you made an amendment, make sure the numbers and periods align to what the IRS has on record. The Instructions for Form 720 explain Part III totals and how amounts flow, use those to double check your math.

Include the stub and package it right

• Confirm the identifying information on Form 15105 is complete – the June 2017 revision of the form has no signature block or jurat, so no signature is required.
• Include the response stub that came with CP183.
• Use the provided window envelope so the IRS address shows correctly, or if you use your own envelope, mail to the address on the notice. The form and notice both direct you to return the response within 30 days of the notice date.

Quick reference table for your team

Step	What to enter	Check against	Proof to retain
Header	EIN, name, tax period	Filed Form 720 header	Copy of filed return
Tax lines	Type, amount, IRS No.	Pub. 510, Instructions for Form 720	Workpapers showing rate x base
Totals	Grand total of abstracts	Form 720 totals	Reconciliation sheet
Submission	Stub, window envelope (no signature required)	CP183 instructions	Mailed copy, tracking

Tip, add the abstract mapping schedule to your close binder so a reviewer can tie every dollar back to source records in minutes.

Where to send Form 15105 and what to include

Your CP183 tells you to return the completed Form 15105 with the response stub, and to make sure the IRS address shows through the envelope window. If you cannot use the provided envelope, mail to the address on the notice, not to the regular Form 720 filing address or a generic IRS service center. Include Form 720 or schedules only if the notice asks for them or if you are clarifying a discrepancy, otherwise focus on the abstract level breakdown the IRS requested. Always keep copies.

Deadlines, penalties, and incomplete account risks

If the IRS does not receive a complete response within 30 days of the CP183 date, your account may be marked incomplete. That status can lead to additional penalties and interest until the IRS can post and reconcile your liability. A timely, accurate Form 15105 package usually stops that snowball before it starts.

When in doubt, respond on time and explain. Include your mapping and a short cover note if you corrected a prior mismatch. If you need more time, call the number on your notice and document the conversation. Notice Topic 651 gives general guidance on what to do when you receive an IRS notice and reminds you to keep copies of everything you send.

Common Form 15105 mistakes to avoid

• Using the wrong or outdated form. Use the official one page Form 15105 PDF, revised June 2017, linked from the CP183 page.
• Mismatched abstract numbers. Confirm the IRS No. for each tax using Publication 510 and the Instructions for Form 720.
• Totals that do not equal the filed return. Reconcile Form 15105 totals to Form 720 for the exact quarter and year.
• Missing response stub or wrong envelope. Include the stub and use the window envelope so the address prints correctly.
• No proof of payment. Attach EFTPS confirmations or bank proof if you are explaining a payment application question. Keep originals and send copies. Notice Topic 651 explains what proof to provide.

Official IRS resources and where to get help

Start with the official pages and current versions. Use Publication 510 for excise categories and references to IRS Nos., use the Instructions for Form 720 for line by line guidance and Part III totals, and use the CP183 page for the response steps and deadlines.

If you need representation, file Form 2848. If you only need someone to receive information, file Form 8821. The IRS now accepts online submissions for both, and a Tax Pro Account can speed processing for individuals.

Taxpayer assistance options

• Call the number on your notice for case specific questions.
• If your case stalls or you face hardship, contact the Taxpayer Advocate Service. The CP183 page links directly to TAS and to Low Income Taxpayer Clinics.
• Keep copies of every document and note every call, date, and time.

Authorized representative guidance

To allow a professional to speak with the IRS about your CP183 and Form 15105, submit Form 2848 and list “Form 720” with the exact tax period. If you only want information shared, submit Form 8821 for those same periods. You can upload both online, and the IRS notes that processing can be faster with the Tax Pro Account in certain situations.

Be precise on the periods you authorize, for quarterly excise, list the quarter and year, for example, 2025 Q2, not “all years.” Form 8821 instructions prohibit general references.

For firms, build delivery that prevents CP183, not more busywork

If you are a managing partner or controller, the cure is structure. Build a small, strong delivery loop around Form 720. Require an abstract mapping schedule in your month end close, use standardized workpapers that show rate, base, and IRS No., and add a reviewer checklist that confirms totals tie to Part I, Part II, and Part III of Form 720 before you file. The IRS makes its expectations clear, match your workflow to those expectations to reduce notices and rework.

Where Accountably helps, only when it adds value

Accountably works with firms that want capacity without chaos. If your team is buried in production, we can help you stand up SOP driven workpapers, enforce abstract number mapping, and add layered review so partners spend less time in cleanup and more time with clients. Our teams work in your systems and templates, and we treat Form 15105 mapping as a standard control inside your Form 720 process. Use this if you want scalable delivery without giving up quality or oversight.

Conclusion

You can close a CP183 cleanly with a precise, well documented Form 15105. Confirm the notice date, hit the 30 day deadline, map every liability to the correct IRS No., and reconcile totals to your filed Form 720. Include the response stub, use the window envelope, and keep copies of everything you send. When you make this mapping part of your regular workflow, CP183 stops being a fire drill and becomes a simple quality check.

Common Mistakes We See Every Season

Every quarter, the same handful of CP183 traps show up across desks. They're small, but each one earns the filer a second notice or a stalled posting at the IRS excise account.

Reusable Checklists

These checklists are copy-paste ready for firm SOPs and engagement folders. Each one mirrors the workflow we run on a CP183 response from intake to mail-out.

Keep 15105 Season From Stalling

CP183 traffic is unusual in that it doesn't arrive on a predictable calendar like quarterly Form 720 deposits. A single missed abstract-number breakdown on a Q1 return can land a CP183 weeks or months later, often after the firm has already closed out the quarter and moved on (per the Form 15105 instructions, Rev. June 2017). The 30-day window starts on the notice date, so the response often has to be turned around before the client even calls in to ask about the letter.

The fix is treating CP183 like its own short engagement instead of a tag-along to Form 720 cleanup. A few small process changes upstream prevent the notice from issuing at all, and a tight response SOP keeps the 30-day clock from becoming a fire drill on the back end.

• Pull abstract numbers from Form 720 Part I and Part II directly into the work paper before the quarterly return is filed, so the breakdown already exists if a CP183 is later issued.
• Reconcile the per-abstract amounts to the total Form 720 liability inside the original quarterly close, not after the notice arrives.
• Standardize the three-row Form 15105 layout plus supplemental-sheet template across every Form 720 engagement, so any preparer can respond without rebuilding the format.
• Calendar the 30-day mail-by date from the notice date the moment a CP183 lands at intake, with a 5-day internal review buffer baked in.
• Keep payment and disclosure separate: settle any open Form 720 balance through the original payment channel, and limit Form 15105 to the abstract-number breakdown.

Accountably's tax delivery teams run this exact intake-to-mail SOP on Form 720 engagements, so CP183 responses go back inside the 30-day window with the abstract-number breakdown already reconciled to the original quarterly return.

FAQs

What is IRS Form 15105 and why did I receive it?

Form 15105 is the IRS response form titled No Breakdown of Liability By Abstract Number on Form 720. You receive it with CP183 when the IRS needs your Form 720 liability broken out by IRS No. for the period on the notice. Complete it, include the response stub, and return it within 30 days.

Where do I find the correct abstract numbers for my taxes?

Use the current Instructions for Form 720 to see which line maps to which IRS No., and Publication 510 to confirm tax categories and descriptions. Match each amount to the correct abstract number before you submit.

Do I need to send a copy of Form 720 with Form 15105?

Send exactly what the notice asks for. CP183 tells you to return the completed Form 15105 with the response stub in the window envelope. Include additional schedules only if the notice requests them or if you need to clarify a discrepancy.

What happens if I miss the 30 day deadline?

Your account may be marked incomplete and you can be charged additional penalties and interest. Mail a complete response as soon as possible, and consider calling the number on your notice to document your status.

Can my CPA speak to the IRS for me about this notice?

Yes, if you file Form 2848 and list the exact Form 720 periods, your CPA can represent you. If you only want them to receive information, use Form 8821. Both can be submitted online.

How do I verify my totals before mailing?

Sum every abstract amount on Form 15105, then match that total to your Form 720 total liability for the same quarter and year. Use the Instructions for Form 720 to double check how Part III and totals should appear.