IRS Form 15105 Guide: Form 720 Abstract Number Breakdown

1. Introduction: What is Form 15105?

IRS Form 15105, officially titled No Breakdown of Liability By Abstract Number on Form 720, is an administrative tax compliance response form published by the Internal Revenue Service (IRS). It is governed by the Excise Tax branch of the IRS Small Business/Self-Employed (SB/SE) Division.

This form is not a regular tax return that businesses file each quarter. Instead, it is sent by the IRS as an enclosure with Notice CP183 to businesses that filed Form 720 (Quarterly Federal Excise Tax Return). Form 15105 is triggered when an employer or business reports an excise tax liability or remits a payment, but fails to itemize that liability across the specific IRS Abstract Numbers assigned to each taxable activity.

2. Purpose of the Form: Why Does Form 15105 Exist?

Unlike corporate income taxes or payroll taxes that flow into the general fund of the United States Treasury, federal excise taxes are statutorily dedicated by Congress to fund specific public trusts. For example, fuel taxes fund the Highway Trust Fund and Airport and Airway Trust Fund, coal taxes fund the Black Lung Disability Trust Fund, sport fishing equipment taxes fund wildlife restoration, and health plan fees fund research institutes.

To ensure money reaches the correct trust fund, Form 720 requires taxpayers to assign every dollar of excise tax to a specific, standardized IRS Number (known as an Abstract Number). If a business enters a lump-sum tax liability on Form 720 without itemizing the individual abstract numbers, the Treasury cannot legally allocate the funds. Form 15105 solves this administrative breakdown by:

• Itemizing Lump-Sum Payments: It provides a structured table where the business specifies exactly which excise categories (fuel, coal, air transportation, communications, etc.) generated the reported tax.
• Correcting Incomplete Tax Returns: It allows the IRS to process an incomplete Form 720 without requiring the taxpayer to prepare and file a formal amended return.
• Preventing Erroneous Penalties: Responding promptly with Form 15105 prevents the IRS from treating the return as unfiled, protecting the business from failure-to-file and failure-to-deposit penalties.

3. Who Needs to File This Form?

Form 15105 is an inquiry-driven document that you only complete if the IRS contacts you directly. You need to complete and return Form 15105 if you meet the following criteria:

• Your business filed Form 720 (Quarterly Federal Excise Tax Return) for a recent calendar quarter.
• You received IRS Notice CP183 stating that your Form 720 is missing essential information because tax liabilities were not broken down by abstract numbers.
• You entered a total tax figure on Part II or Part III of Form 720, but omitted the detailed line-item calculations in Part I or Part II.
• You are a business owner, corporate officer, or authorized tax professional responding on behalf of the excise taxpayer.

4. Who Is Exempt / Not Required to File?

Because Form 15105 is an error-resolution document, the vast majority of businesses will never need to use it:

• Compliant Form 720 Filers: Businesses that properly itemize their excise tax calculations on the correct abstract lines of Form 720 have no reporting omissions and do not receive this form.
• Businesses Not Subject to Excise Taxes: Companies that only file income tax returns (Form 1120 or Form 1065) and payroll returns (Form 941) never handle Form 15105.
• Individual Taxpayers: Everyday consumers and wage earners do not file federal quarterly excise tax returns and have no reason to use this document.
• Businesses That Have Not Received Notice CP183: If you realize you made an error on Form 720 before receiving Notice CP183, you file an amended return using Form 720-X rather than Form 15105.

5. When to File: Deadlines and Frequency

Form 15105 is an event-based response document rather than a recurring quarterly tax return. It carries an urgent statutory response window.

The submission deadline is printed directly on your Notice CP183, which is strictly 30 calendar days from the date of the notice. Meeting this 30-day deadline is essential: Notice CP183 explicitly warns that failing to provide the missing abstract breakdown within 30 days can cause the IRS to reject the return as incomplete, triggering failure-to-file penalties, failure-to-deposit penalties, and compounding interest. If you need extra time to consult sales ledgers, call the telephone number listed on Notice CP183 before the 30 days expire to request an extension.

6. Where and How to File

Form 15105 is a paper-based document that cannot be filed through commercial tax software. You must return it directly to the IRS campus processing your excise return:

• Pre-Addressed Return Envelope: Use the return envelope provided with Notice CP183 so the correct IRS excise processing unit address appears through the window.
• Mailing Address: If you misplaced the return envelope, mail the completed Form 15105 to the designated IRS address as per instructions printed directly on your Notice CP183 (typically an IRS Processing Center in Cincinnati, Ohio, or Ogden, Utah).
• Certified Mail Recommended: Always mail your response via certified mail with return receipt requested to maintain verifiable proof that you responded within the 30-day deadline.
• Do Not Attach a Check: Form 15105 is an informational breakdown, not a payment voucher. Any tax payments should have been remitted with the original return or through EFTPS.

7. Step-by-Step Instructions to Fill Form 15105

Form 15105 is a straightforward, single-page document. It captures business contact details and provides a clear grid to itemize your tax liabilities. The table below outlines each section of the form.

Section	Item Name	Required Information & Instructions
Header	Business Identification	Nine-digit Employer Identification Number (EIN), legal business name, and tax period quarter.
Contact Info	Address & Telephone	Current business mailing address, address change indicator, primary and secondary phone numbers.
Column 1	Type of Tax	Written description of each taxable product or service (e.g., gasoline, coal, air transportation).
Column 2	IRS Number (Abstract No.)	The specific 1- to 3-digit IRS Number assigned to that tax type on Form 720.
Column 3	Amount Applied	Exact dollar amount of excise tax liability attributed to each specific abstract number.
Bottom Line	Total Tax	The sum of all itemized amounts, which must match the total tax reported on your original Form 720.

Part 1: Business and Contact Information

Enter your business’s nine-digit Employer Identification Number (EIN) at the top of the form. Provide the complete legal business name exactly as reported on your original Form 720. Enter the specific tax period ending date (for example, March 31, June 30, September 30, or December 31). Provide your current mailing address, check the box if your address has changed, and include primary and secondary daytime phone numbers.

Part 2: Breaking Down Liabilities by Abstract Number

In the main breakdown table, you must reconcile your total excise tax liability by categorizing your payments:

• Type of Tax: In the first column, write the specific category of excise tax you owe (such as Diesel Fuel, Kerosene, Coal, Local Telephone Service, Transportation of Persons by Air, or PCORI fee).
• IRS Number (Abstract Number): In the middle column, enter the official IRS Number assigned to that tax on Form 720. For example:
  • Gasoline: IRS No. 62
  • Diesel Fuel: IRS No. 60
  • Aviation Gasoline: IRS No. 14
  • Transportation of Persons by Air: IRS No. 26
  • Local Telephone and Communications: IRS No. 22
  • Coal (Underground): IRS No. 36 or 37
  • Indoor Tanning Services: IRS No. 140
  • Patient-Centered Outcomes Research (PCORI) fee: IRS No. 133
• Amount Applied: In the right-hand column, enter the exact dollar amount of tax owed for that specific category.

Part 3: Reconciling the Total

Sum all the amounts entered in the right-hand column and enter the total at the bottom of the table. This total must equal the total tax reported on your original Form 720. If the numbers do not match, the IRS cannot reconcile your account, which will result in follow-up inquiries.

8. Required Documents and Information Needed Before Filling

Before completing Form 15105, assemble the following accounting and tax records:

• The original Notice CP183 received from the IRS.
• A copy of the original Form 720 filed for the quarter under review.
• Internal production ledgers, fuel gallon summaries, flight manifests, or billing records showing how your excise taxes were calculated.
• IRS Publication 510 (Excise Taxes): Used to verify the correct IRS Abstract Numbers and tax rates.
• A copy of your Electronic Federal Tax Payment System (EFTPS) deposit receipts confirming that payments cleared.
• A signed Form 2848 (Power of Attorney) if a CPA or enrolled agent represents your business.

9. Common Mistakes to Avoid

Failing to complete Form 15105 properly can prolong your excise tax inquiry. Avoid these frequent mistakes:

• Entering Incorrect Abstract Numbers: Confusing similar tax categories—such as entering IRS No. 62 for aviation gasoline instead of IRS No. 14—causes your tax payments to be routed to the wrong federal trust fund.
• Total Amount Discrepancies: The sum of the itemized taxes on Form 15105 must tie out exactly to the total tax reported on your original Form 720. If your numbers differ, the IRS will reject the form.
• Filing Form 720-X Prematurely: Notice CP183 asks specifically for Form 15105. Submitting an amended Form 720-X instead can confuse processing systems and delay resolution.
• Ignoring Notice CP183: Assuming that because you paid the tax, the IRS will figure out the breakdown is dangerous. The IRS cannot guess which trust fund receives your money; ignoring the notice triggers automated penalties.
• Missing the 30-Day Response Window: Failing to respond within 30 calendar days allows the IRS to assess failure-to-file and failure-to-pay penalties against your account.

10. Penalties for Non-Filing or Errors

While Form 15105 itself does not carry direct statutory fines, failing to respond to Notice CP183 triggers severe administrative and financial consequences:

• Invalid Return Treatment: If you fail to provide the required abstract breakdown, the IRS may treat your original Form 720 as incomplete or unfiled under Treasury regulations.
• Failure-to-File Penalties: Under Internal Revenue Code Section 6651(a)(1), the penalty for an unfiled or invalid return is 5% of the unpaid tax for each month the return is late, up to a maximum of 25%.
• Failure-to-Deposit Penalties: Because excise taxes must be deposited semi-monthly for most categories, failing to provide the abstract breakdown can cause the IRS to misapply deposits, triggering penalties under Section 6656 ranging from 2% to 15%.
• Compounding Statutory Interest: Any unpaid or unallocated tax balance accrues mandatory interest from the original quarterly due date until fully resolved.

11. Related Forms or Schedules

Form 15105 operates within an interconnected system of federal excise tax forms and compliance publications:

• Form 720: Quarterly Federal Excise Tax Return (the primary return being corrected).
• Form 720-X: Amended Quarterly Federal Excise Tax Return (used to correct mathematical errors or claim adjustments).
• Form 6627: Environmental Taxes (attached to Form 720 for chemical and petroleum excise taxes).
• Notice CP183: Notice of Missing Abstract Breakdown on Form 720 (the triggering notice).
• IRS Publication 510: Excise Taxes (Including Fuel Tax Credits and Refunds).
• Form 2848: Power of Attorney and Declaration of Representative.

12. Frequently Asked Questions (FAQs)

1. What is an IRS Abstract Number on Form 720?

An IRS Abstract Number (or IRS No.) is a specific one- to three-digit identification code printed on Form 720 that identifies a particular type of federal excise tax, such as IRS No. 62 for gasoline or IRS No. 26 for commercial air transportation.

2. Why does the IRS need an abstract breakdown if I already paid my taxes?

Federal excise taxes do not go into general government revenue; they are legally dedicated to specific federal trust funds established by Congress. The IRS requires the abstract breakdown to ensure your tax dollars are deposited into the correct statutory trust fund.

3. What should I do if I cannot find the correct abstract number for my tax?

You can locate every valid abstract number by reviewing the left and right margins of Form 720, or by consulting IRS Publication 510 (Excise Taxes), which provides an index of all taxable products and their assigned IRS numbers.

4. Does submitting Form 15105 mean my business is under an audit?

No. Notice CP183 and Form 15105 represent an administrative correction process, not a formal audit. The IRS is simply asking for the missing classification details so it can process your return accurately.

5. What if the actual tax breakdown differs from the total I reported on Form 720?

If you discover that your original Form 720 total was mathematically incorrect, you should complete Form 15105 to match the original return total, and simultaneously submit an amended return using Form 720-X to correct the underlying tax liability.

6. Can I submit Form 15105 electronically?

No. Form 15105 must be completed on paper and returned via mail to the IRS processing address listed on your Notice CP183.

13. Conclusion: Key Takeaways

IRS Form 15105 is an essential administrative tool that ensures federal excise taxes are properly accounted for and directed to their designated federal trust funds. By providing a clear breakdown of your Form 720 tax liability across specific IRS Abstract Numbers within 30 days of receiving Notice CP183, your business can resolve reporting omissions quickly.

Because excise tax rules involve complex industry definitions, strict semi-monthly deposit schedules, and severe late-filing penalties, business owners should review their quarterly ledgers carefully, verify abstract numbers in Publication 510, and partner with a qualified CPA or excise tax specialist when completing Form 15105.