When must the IRS accept an installment agreement under IRC 6159(c)?

IRC 6159(c) requires the IRS to enter into an installment agreement -- the guaranteed installment agreement -- when all of the following conditions are met: (1) the taxpayer is an individual; (2) the aggregate unpaid tax for the taxable year (not counting interest, penalties, and additions to tax) does not exceed $10,000; (3) the taxpayer has filed all required returns and paid all taxes on time during the prior 5 years (no default on a prior IA during that period); (4) the taxpayer is financially unable to pay the full liability when due; and (5) the taxpayer agrees to pay the full liability, with interest and penalties, within 3 years. When all conditions are met, the IRS cannot decline the agreement on discretionary grounds. Verify current procedures at IRS.gov.

Does an installment agreement toll the collection statute of limitations?

Yes. Under IRC 6159(f), the period of limitations on collection under IRC 6502 (the 10-year CSED) is tolled for the entire period any installment agreement is in effect, plus 30 days after termination. The tolling also applies to the period during which a proposed installment agreement is pending (under IRS review and awaiting acceptance or rejection), plus 30 days thereafter. A taxpayer who has been on an installment agreement for 5 years has effectively given the IRS 5 additional years to collect beyond the original 10-year CSED. This is one of the most significant hidden costs of an installment agreement and should be disclosed to every client before entering an IA. Verify current tolling rules at IRS.gov and IRM 5.14.1.

What are the four tiers of IRS installment agreements?

The four tiers of installment agreements are: (1) Guaranteed IA (IRC 6159(c)): mandatory acceptance for individual taxpayers owing $10,000 or less in tax (excluding interest and penalties), payable within 3 years, with 5-year filing and payment compliance; (2) Streamlined IA (IRS administrative policy): for liabilities up to $50,000 (including interest and penalties), payable within 72 months, no financial disclosure required; (3) Non-Streamlined IA: for liabilities over $50,000 or when the streamlined terms cannot be met, requires Form 433-A or 433-B financial disclosure, subject to IRS discretion; and (4) Partial Pay IA (PPIA): when the taxpayer cannot pay in full within the CSED, monthly payments based on demonstrated ability to pay, IRS reviews every 2 years and may increase payments. Verify current thresholds and procedures at IRS.gov.

Does interest continue to accrue during an installment agreement?

Yes. An installment agreement does not suspend interest accrual under IRC 6601 or the late payment penalty under IRC 6651(a)(2). Under IRC 6159(d), the Secretary is required to establish terms that include all amounts due, and interest and additions to tax continue to accrue throughout the agreement's duration. This means a taxpayer's monthly IA payment must exceed the monthly interest and penalty accrual or the outstanding balance will grow despite regular payments. Before committing a client to an IA, calculate whether the proposed monthly payment exceeds the monthly accrual rate and ensure the client understands the total amount that will be paid over the agreement's term.

What happens if a taxpayer defaults on an installment agreement?

Under IRC 6159(b)(3) and IRC 6159(e), the IRS must provide at least 30 days notice before modifying or terminating an installment agreement for cause. The notice must explain the reason for the intended action and give the taxpayer an opportunity to demonstrate that the basis for modification or termination is erroneous. If the IRS proceeds with termination, the full outstanding balance becomes immediately due and the IRS regains levy authority without issuing a new final notice of intent to levy for the same assessment. A taxpayer who has received a termination notice should immediately contact the Revenue Officer or request a Collection Appeals Program (CAP) review within the notice period. Verify current default procedures at IRS.gov.

How does the installment agreement interact with levy action under IRC 6343?

An approved installment agreement triggers mandatory levy release under IRC 6343(a)(1)(C), unless the IA terms expressly provide that the levy is to continue. A pending IA application is NOT an approved agreement and does not trigger mandatory levy release -- the levy continues while the IRS evaluates the application. Once the IA is approved and the levy is released, the IRS generally cannot re-levy while the IA remains in good standing. If the IA is terminated, the IRS regains levy authority for the same assessment without issuing a new final notice of intent to levy. Practitioners should confirm IA approval in writing (IRS Letter 2159 or equivalent) before representing to a client that the levy has been or must be released.

IRC 6159: Installment Agreement Statute

Q: What does IRC 6159 authorize?

IRC 6159(a) authorizes the Secretary of the Treasury to enter into installment agreements with taxpayers to allow payment of any tax liability in installments, when the Secretary determines the agreement will facilitate full or partial collection. The statute creates a general discretionary authority to accept installment agreements, an absolute mandatory acceptance rule for small liabilities (IRC 6159(c)), and rules for the agreement's terms, modification, default, and the tolling effect on the collection statute of limitations. Verify current IRS installment agreement procedures at IRS.gov.

Q: What is a Partial Pay Installment Agreement (PPIA)?

A Partial Pay Installment Agreement (PPIA) is an installment agreement under which the taxpayer's monthly payments are based on demonstrated ability to pay rather than on full repayment of the liability within the CSED. As a result, the taxpayer will not fully pay the balance before the collection period expires, and the remaining unpaid balance may become unenforceable when the CSED runs. The IRS reviews PPIA terms every 2 years and may increase the monthly payment if the taxpayer's financial condition improves. The PPIA is most advantageous when the CSED has not been significantly tolled and the taxpayer has a genuine inability to pay. Verify current PPIA procedures and Form 433-A requirements at IRS.gov.

1. What IRC 6159 Does

IRC 6159 is the primary statutory authority for IRS installment agreements. It gives the Secretary of the Treasury discretionary authority to accept installment payment arrangements when the arrangement will facilitate collection, and it creates an absolute mandatory acceptance obligation for qualifying small liabilities under IRC 6159(c). The statute also establishes rules for agreement terms, interest and penalty accrual during an IA, the taxpayer's right to notice before modification or termination, and -- critically -- the tolling of the collection statute of limitations for every day an IA is in effect.

The companion procedural guide covers the Form 9465 filing process, payment methods, online payment agreement tools, and the administrative steps for requesting and modifying agreements. This guide addresses the statutory framework: what the IRS must accept, what an IA costs beyond the stated payments, and when and how an IA can be modified or terminated.

2. General Authority and Four IA Tiers

IRC 6159(a) grants the Secretary broad authority to enter into installment agreements when the Secretary determines that an agreement "will facilitate full or partial collection of such liability." This permissive standard gives the IRS discretion to decline an agreement when it determines collection would be better served by levy -- except where the mandatory acceptance rule of IRC 6159(c) applies.

In practice, IRS administrative policy has created four tiers of installment agreements that apply the IRC 6159 framework at different liability levels:

Tier 1 -- Guaranteed IA (IRC 6159(c)): Mandatory for individual taxpayers owing $10,000 or less in unpaid tax (excluding interest, penalties, and additions). Must be paid within 3 years. No financial disclosure required. IRS has no discretion to refuse if all conditions are met.
Tier 2 -- Streamlined IA (IRS administrative policy): For liabilities up to $50,000 (including interest and penalties as of the date of application), payable within 72 months. No Form 433-A financial disclosure required. IRS processes without in-depth financial review. Verify current threshold at IRS.gov.
Tier 3 -- Non-Streamlined IA: For liabilities over $50,000 or when the taxpayer cannot pay within 72 months. Requires a completed Form 433-A (individuals) or Form 433-B (businesses) financial disclosure. Monthly payment based on demonstrated ability to pay after allowable expenses. Subject to full IRS Collection financial review.
Tier 4 -- Partial Pay IA (PPIA): When the taxpayer cannot pay the full liability before the Collection Statute Expiration Date (CSED) runs. Monthly payments based on ability to pay; the IRS anticipates collecting less than the full balance. IRS reviews terms every 2 years and may modify upward if financial condition improves.

3. The Guaranteed Installment Agreement (IRC 6159(c))

When All Conditions Are Met, the IRS Cannot Refuse the Guaranteed IA

The guaranteed installment agreement under IRC 6159(c) is the taxpayer's strongest IA right: when all five statutory conditions are met, the IRS is legally required to accept the agreement and cannot exercise discretion to deny it. Practitioners should identify every case where these conditions are satisfied -- particularly for clients who owe modest amounts and have a solid compliance history -- and use the guaranteed IA to avoid financial disclosure and IRS discretionary review. A properly submitted guaranteed IA request that is wrongfully rejected can be challenged through the Collection Appeals Program (CAP) or CDP hearing.

The five conditions for mandatory guaranteed IA acceptance under IRC 6159(c) are:

Individual taxpayer only: The guaranteed IA applies only to individuals. Business entities (corporations, partnerships, LLCs) are not eligible for the guaranteed IA.
Aggregate tax liability does not exceed $10,000: The $10,000 threshold is measured by the aggregate unpaid tax for the taxable year, NOT including interest, penalties, or additions to tax. A taxpayer who owes $9,000 in underlying tax but $15,000 total (including penalties and interest) still qualifies. Verify current thresholds at IRS.gov.
Five-year compliance history: During the 5 years preceding the request, the taxpayer must have timely filed all required returns, timely paid all taxes, and must not have previously had an installment agreement under IRC 6159 that was in default or entered into.
Financial inability to pay the full amount when due: The taxpayer must be unable to pay the tax in full when it is due. This is typically established by showing that immediate full payment would require liquidating assets or borrowing at hardship rates.
Agreement to full payment within 3 years: The taxpayer must agree to pay the entire outstanding liability (tax plus interest and penalties) within 3 years and to remain in full tax compliance during the agreement period.

4. The CSED Tolling Effect (IRC 6159(f)) -- The Hidden Cost

An IA Tolls the CSED -- Every Day of the Agreement Extends the IRS's Collection Window

Under IRC 6159(f), the 10-year collection statute of limitations under IRC 6502 is tolled for the entire period any installment agreement -- including a proposed agreement under IRS review -- is in effect, plus 30 days after it terminates. A client who enters an IA today and maintains it for 7 years has given the IRS a 17-year total collection window on the day the IA terminates (10 original years + 7 years of tolling + 30-day tail). This must be disclosed before the client agrees to an IA. For clients who have been on an IA for years or who have a CSED approaching, the tolling calculation may be the most important number in the engagement.

IRC 6159(f) tolls the collection statute during:

The pendency of a proposed IA: From the date the taxpayer submits an IA request to the date the IRS accepts or rejects it, the CSED is tolled. This includes the entire processing period, which can be weeks or months.
The active IA period: From IA acceptance to termination or full payment, every day of the agreement tolls the CSED.
30 days after termination: The CSED tolling extends for 30 days after the IA terminates (whether by default, mutual agreement, or payment in full).

Practitioners should calculate the CSED for every installment agreement client, including all tolling events that preceded the current IA (bankruptcy, OIC submissions, CDP hearings, prior IAs, and the like). For clients with a CSED approaching, consider whether a PPIA or an OIC under IRC 7122 would be a better strategy, since a PPIA that survives to the CSED expiration results in the remaining balance becoming unenforceable.

5. Interest and Penalty Accrual During an IA (IRC 6159(d))

Monthly IA Payments Must Exceed Monthly Interest Accrual or the Balance Grows

An installment agreement does not suspend the accrual of interest under IRC 6601 or the failure-to-pay penalty under IRC 6651(a)(2). Under IRC 6159(d), both continue throughout the agreement's term. For a client with a large balance, the monthly interest accrual (currently calculated at the federal short-term rate plus 3 percentage points) can be substantial. If the agreed monthly payment is less than the monthly interest and penalty accrual, the outstanding balance will INCREASE despite regular payments. Before executing an IA, calculate: (1) the monthly accrual rate, (2) the minimum payment needed to prevent balance growth, and (3) the total amount the client will pay over the IA's projected term.

The interest rate applicable to outstanding tax liabilities is the federal short-term rate plus 3 percentage points under IRC 6621(a)(2), compounded daily under IRC 6622. The failure-to-pay penalty under IRC 6651(a)(2) continues to accrue at 0.5% per month (with a ceiling of 25% of the unpaid tax) but is reduced to 0.25% per month while an approved IA is in effect. Verify current IRS interest rates (published quarterly) at IRS.gov.

The practical implication is that a client on a long-term IA paying the minimum may pay significantly more than the original tax liability by the time the agreement is satisfied. Full disclosure of the total projected cost -- tax, interest, and penalties through projected payoff -- is essential to informed client consent.

6. Modification, Default, and Termination (IRC 6159(b)(2)-(3) and IRC 6159(e))

IA Termination Restores Levy Authority on the Same Assessment Without a New CDP Notice

When an installment agreement is terminated for cause, the IRS regains full levy authority on the affected assessment without issuing a new final notice of intent to levy for that tax period. The CDP levy notice was already issued before the IA was entered; the IA suspension of levy action ends with the agreement. A taxpayer who allowed a CDP hearing to expire (or whose CDP rights were exhausted) before entering the IA will have no CDP hearing right after the IA terminates. The only available administrative remedy at that point is a Collection Appeals Program (CAP) request, which does not suspend levy action and has no Tax Court review. Understand the post-termination levy exposure before allowing an IA to default.

Under IRC 6159(b)(2), the Secretary may modify the terms of an installment agreement if the taxpayer's financial condition changes significantly. Under IRC 6159(b)(3), the Secretary may terminate an installment agreement for cause, but must provide the required advance notice under IRC 6159(e) before doing so.

Under IRC 6159(e), before modifying or terminating an IA, the IRS must:

Provide the taxpayer with at least 30 days notice (Notice CP523 or equivalent) explaining the reasons for the intended modification or termination.
Give the taxpayer an opportunity to demonstrate that the grounds for modification or termination are erroneous.
Not take the modification or termination action until the 30-day period has expired and any appeals have been resolved.

Common grounds for IA termination include: missed payments, failure to file a required return during the IA period, failure to pay a tax that becomes due after the IA is entered, discovery that the taxpayer provided false or inaccurate financial information, and jeopardy to collection. When a Notice CP523 arrives, the practitioner should immediately determine the basis for the default and respond within the 30-day window. A CAP request challenging the termination must be filed within the notice period; it does not suspend levy action but preserves the administrative record. Verify current default and appeals procedures at IRS.gov and IRM 5.14.10.

7. Partial Pay Installment Agreement (PPIA)

PPIA Is Most Valuable When the CSED Has Not Been Significantly Tolled

A PPIA is strategically effective when the taxpayer has a genuine inability to pay and the CSED has not been significantly tolled by prior IAs, OIC submissions, bankruptcy, or other events. In that scenario, the taxpayer makes modest monthly payments, the CSED runs while the IA is in effect (continuing to toll it), and the remaining balance may become unenforceable when the original collection period -- extended only by tolling during the IA itself -- finally expires. Before recommending a PPIA over an OIC, calculate the effective CSED, model the payment schedule, and determine whether a DATC OIC under IRC 7122 would result in a better outcome at a lower total cost. The IRS will also review the PPIA every 2 years and can increase payments if the taxpayer's financial condition improves.

A PPIA is available when the taxpayer's demonstrated ability to pay (monthly disposable income after IRS allowable expenses) multiplied by the remaining collection period produces a figure less than the total outstanding liability. Unlike a full-pay IA, a PPIA acknowledges that the IRS expects to collect less than 100% of the balance.

IRS Form 433-A (Collection Information Statement) is required for PPIA requests. The IRS evaluates the taxpayer's income, expenses, assets, and liabilities to determine the allowable monthly payment. Equity in assets is reviewed and the IRS may require the taxpayer to liquidate or borrow against non-exempt assets before accepting a PPIA. Verify current PPIA procedures and Form 433-A instructions at IRS.gov and IRM 5.14.2.

8. Interaction with Levy Release (IRC 6343) and OIC (IRC 7122)

An installment agreement intersects directly with two other collection statutes addressed in companion guides:

Levy Release (IRC 6343)

An approved installment agreement triggers mandatory levy release under IRC 6343(a)(1)(C), unless the IA expressly provides that the levy continues. This is one of the most powerful practical effects of obtaining an IA: any bank levy, wage levy, or receivables levy against the client must be released once the IA is approved. A pending IA application does NOT trigger mandatory release; the levy remains in place until the agreement is actually approved. Confirm approval in writing before representing that the levy is released.

OIC vs. IA (IRC 7122)

For a client who cannot pay the full liability, an OIC under IRC 7122 and an installment agreement under IRC 6159 are the two primary resolution paths. Key differences:

An accepted OIC resolves the liability for less than the full amount; an IA always requires full repayment (with interest) or, in a PPIA, as much as the taxpayer can afford within the CSED window.
An OIC submission tolls the CSED under IRC 6503 during evaluation; an IA tolls it under IRC 6159(f) throughout its term. Both toll the CSED, but the OIC toll is typically shorter.
An IA preserves the tax lien; an accepted OIC requires lien release after full compliance with the offer terms.

For clients with a Reasonable Collection Potential (RCP) near or below the outstanding liability, an OIC is likely the better long-term outcome. For clients whose RCP clearly exceeds the liability but who need structured payments, an IA is the appropriate path.

9. OBBBA: No Direct Amendments to IRC 6159

The One Big Beautiful Bill Act (OBBBA, Pub. L. 119-21, enacted July 4, 2026) did not amend IRC 6159. The guaranteed IA conditions, CSED tolling rule, interest accrual framework, modification and termination notice requirements, and the four-tier structure all remain unchanged from their pre-OBBBA form.

Practitioners should monitor IRS.gov for OBBBA-related guidance that may affect IA processing indirectly -- for example, through changes to IRS collection financial standards (which affect the allowable expenses calculation in non-streamlined and PPIA requests) or through changes to IRS interest rates under IRC 6621 that affect the monthly accrual calculation. Verify current rates and standards at IRS.gov before completing any financial disclosure.

10. Strategic Considerations

Always Calculate the CSED Before Recommending an IA

The CSED tolling under IRC 6159(f) is the most consistently overlooked cost of an installment agreement. Before recommending an IA for any client, calculate: (1) the original assessment date for each period; (2) all prior tolling events; (3) the current CSED; and (4) how many additional years the proposed IA will add to the collection period. For a client with 2 years left on the CSED, entering a 6-year IA extends the IRS's collection window to approximately 8 years from today -- a significant strategic concession.

Use the Guaranteed IA When Conditions Are Met

For individual clients owing $10,000 or less in underlying tax with 5 years of clean compliance, the guaranteed IA requires no financial disclosure and no IRS discretion. This is the fastest, lowest-friction resolution path for qualifying clients and should be the default recommendation before considering more burdensome non-streamlined or PPIA arrangements.

Model Total Cost Before Executing Any IA

Disclose the projected total payment -- tax plus all interest and penalty accrual through the projected payoff date -- before the client commits to an IA. A $30,000 tax liability paid over 72 months at current interest rates will result in total payments materially above $30,000. The client must understand this before agreeing to the arrangement.

Monitor PPIA Reviews

The IRS reviews PPIA terms every 2 years. Client financial improvements -- new employment, sale of property, receipt of an inheritance -- may trigger a payment increase. Advise PPIA clients to contact you before any major financial change so the disclosure can be managed proactively rather than reactively.

11. Claims and Positions Taken in This Guide

Practitioner Claims Notice

This guide makes the following representations or relies on the following legal and factual positions. Each should be verified against current law, IRS guidance, and the specific facts of any client matter before being cited in a tax return, advice letter, or litigation submission.

#	Claim or Position	Authority / Status
1	IRC 6159(a) authorizes the Secretary to enter into installment agreements when the agreement facilitates collection	IRC 6159(a); Treas. Reg. 301.6159-1; verify at IRS.gov
2	Guaranteed IA: IRS must accept when individual taxpayer owes $10,000 or less in aggregate tax (not counting interest and penalties), 5-year clean history, agrees to pay within 3 years	IRC 6159(c); verify current thresholds at IRS.gov
3	The CSED is tolled for the full duration of any IA (including pending proposed IA) plus 30 days after termination under IRC 6159(f)	IRC 6159(f); IRC 6502; Treas. Reg. 301.6159-1(h); verify at IRS.gov
4	Interest under IRC 6601 and failure-to-pay penalty under IRC 6651(a)(2) continue to accrue during an IA; penalty rate reduced to 0.25% per month while approved IA is in effect	IRC 6601; IRC 6651(a)(2); IRC 6651(h); verify current rates at IRS.gov
5	IRS must provide at least 30 days notice before modifying or terminating an IA for cause; taxpayer has right to demonstrate the grounds are erroneous	IRC 6159(b)(3); IRC 6159(e); verify at IRS.gov and IRM 5.14.10
6	IA termination restores levy authority without a new final notice of intent to levy for the same assessment period	IRC 6330(f); Treas. Reg. 301.6330-1(b)(1); verify at IRS.gov
7	An approved IA triggers mandatory levy release under IRC 6343(a)(1)(C); a pending IA application does not	IRC 6343(a)(1)(C); Treas. Reg. 301.6343-1(b)(3); verify at IRS.gov
8	Streamlined IA threshold is $50,000 including interest and penalties, payable within 72 months; this is IRS administrative policy, not a statutory threshold	IRM 5.14.5; verify current threshold at IRS.gov (subject to IRS policy changes)
9	PPIA terms reviewed by IRS every 2 years; IRS may increase monthly payment if financial condition improves	IRM 5.14.2; Treas. Reg. 301.6159-1(e); verify at IRS.gov
10	OBBBA (Pub. L. 119-21, enacted July 4, 2026) did not amend IRC 6159; installment agreement statutory framework unchanged	Review of OBBBA enacted text; verify at IRS.gov for any implementing guidance

Frequently Asked Questions

What does IRC 6159 authorize?

IRC 6159(a) authorizes the Secretary to enter into installment agreements when the arrangement will facilitate collection. The statute also creates a mandatory acceptance rule for liabilities under $10,000 (IRC 6159(c)), governs the terms and modification of agreements (IRC 6159(b)), requires 30-day notice before termination (IRC 6159(e)), addresses interest accrual during an IA (IRC 6159(d)), and tolls the collection statute for the full agreement duration (IRC 6159(f)). Verify current procedures at IRS.gov.

When must the IRS accept a guaranteed IA under IRC 6159(c)?

The IRS must accept a guaranteed IA when the taxpayer is an individual, the aggregate unpaid tax does not exceed $10,000 (excluding interest and penalties), the taxpayer has 5 years of clean filing and payment history, the taxpayer cannot pay in full when due, and the taxpayer agrees to full payment within 3 years. When all conditions are met, the IRS has no discretion to refuse. A wrongful rejection can be challenged through CAP or CDP.

Does an installment agreement toll the CSED?

Yes. Under IRC 6159(f), the CSED is tolled for the entire period any IA (including a proposed IA under IRS review) is in effect, plus 30 days after it terminates. Every year on an IA is a year added to the IRS's effective collection window. For clients whose CSED is approaching, this must be disclosed and weighed against alternatives such as a PPIA, OIC, or currently not collectible status.

What are the four IA tiers?

(1) Guaranteed IA (IRC 6159(c)): mandatory, liability under $10,000, within 3 years; (2) Streamlined IA (IRS policy): liability up to $50,000 including interest and penalties, within 72 months, no financial disclosure; (3) Non-Streamlined IA: over $50,000 or longer term, requires Form 433-A/433-B financial disclosure; (4) Partial Pay IA (PPIA): payment based on ability to pay, expects less than full repayment within the CSED. Verify current thresholds at IRS.gov.

Does interest accrue during an installment agreement?

Yes. Interest under IRC 6601 and the failure-to-pay penalty under IRC 6651(a)(2) continue to accrue throughout an IA. The FTP penalty rate is reduced to 0.25% per month while an approved IA is in effect (from the standard 0.5%). Monthly payments must exceed monthly accrual to reduce the balance. Calculate the total projected cost before committing a client to an IA term.

What happens when an installment agreement defaults?

The IRS must provide at least 30 days notice under IRC 6159(e) before terminating for cause, with an opportunity to dispute the grounds. After termination, the full balance is immediately due and the IRS regains levy authority without a new CDP notice for the same assessment. A CAP request can be filed within the notice period to challenge termination, but it does not suspend levy action. There is no Tax Court review of a CAP determination.

What is a Partial Pay Installment Agreement (PPIA)?

A PPIA allows a taxpayer who cannot fully pay the liability within the remaining CSED to make monthly payments based on demonstrated ability to pay. The IRS expects to collect less than the full balance. Terms are reviewed every 2 years; payments may increase if the taxpayer's financial condition improves. The PPIA is most beneficial when the CSED has not been heavily tolled and the remaining balance may become unenforceable when the collection period expires. Form 433-A financial disclosure is required.

Does an approved IA release an IRS levy?

Yes. An approved installment agreement triggers mandatory levy release under IRC 6343(a)(1)(C) unless the IA terms expressly allow the levy to continue. A pending IA application does not trigger release -- the levy remains in place during processing. If the IA is later terminated, the IRS regains levy authority on the same assessment without a new CDP notice. Always confirm IA approval in writing before representing that a levy has been released.