May 08, 2026

Are Municipal Bond Investors Sitting on a Ticking Tax Bomb?

How to determine if your clients are affected and how to address this issue

By Ed Mahaffy, MBA, CFP®, ChFC

Mitigating ordinary income tax liability on tax exempt municipal bonds is unlikely to appear on the typical list of tax mitigation strategies. Arguably, it should.

The so-called de minimis rule imposes ordinary income tax liability on tax exempt municipal bonds purchased at a discount exceeding 0.25% per year until maturity. Consider the following example:

A Dallas Independent School District featuring a 2.0% coupon and five-year maturity, issued at 100 and purchased at 86.00 to yield 5.10% to maturity and held to maturity by the purchaser. The lowest purchase price allowed on this bond before the de minimis rule is applied would be 98.75.

The bond in this example would appear to be subject to long-term capital gains tax, however, because the discount exceeds 0.25% per year; the entire discount is subject to ordinary income taxation, per the de minimis rule. Therefore, the “true yield” – the yield after all taxation, is only 4.00% versus 5.10%. Quite a difference – a yield mirage. And the tax bill is not due until maturity or disposition.

Monitoring clients’ purchase prices for individual municipal bonds is typically beyond the CPA’s scope of the engagement. This is information that the client’s financial advisor should communicate to their CPA. Of course, avoiding deeply discounted municipal bonds altogether may make the most sense. However, when the yield seems so attractive and the idea of scooping up bonds at 86 cents on the dollar is so compelling, it is easy to see how one might fall victim to the yield mirage described above.

The comparative analysis is simple. Compare the true yield of the discounted bond to that of similar bonds trading at or above 100.00, bonds that escape both de minimis as well as capital gains taxation.

The solution is equally simple. Sell the bonds subject to de-minimis treatment and purchase bonds with higher coupons – coupons generous enough to command prices that avoid de minimis treatment.

I have managed investment grade municipal bonds for individuals, trusts and financial institutions for decades. De minimis is an issue that typically materializes when the bond market experiences spikes in interest rates, most recently when the federal reserve rapidly hiked rates over 500 basis points in 2022-2023, causing bond prices to plummet and the worst bond market performance since the Civil War.

After years of near zero interest rates, advisors and investors alike have largely forgotten about the de minimis rule. Unfortunately, they will experience a rude awakening at maturity unless action is taken. At the present time, the bond market is providing a nice opportunity to sell bonds purchased at a deep discount at or near their purchase price or accreted cost basis, and to swap into higher coupon alternatives.

Unfortunately, there is no way to avoid the accretion of ordinary income tax liability that has already occurred between the purchase date and the present. However, this is a small price to pay to avoid the additional ordinary income tax liability associated with holding the bond until maturity. And the longer the maturity, the less onerous the accretion.

In short, the de minimis rule as it pertains to clients’ municipal bond holdings should be viewed as an opportunity for financial advisors and tax counsel alike to exercise leadership in disarming this ticking tax bomb. The situation described herein is a glaring example of the need for better communication among financial advisors and tax counsel.

Tax Liability on Municipal Bonds: What CPAs Need to Know

  • The de minimis rule can turn discounted tax exempt municipal bonds into ordinary taxable income, creating surprise tax bills.
  • Many clients and advisors overlook this, especially after rate spikes that caused deep bond discounts.
  • The result is a “yield mirage” – apparent yields that look attractive but drop significantly after tax.
  • This article shows how to compare true after tax yield and recommends swapping out of bonds subject to de minimis treatment.
  • Understanding this helps CPAs protect clients and strengthen the CPA's role as advisor.

 

About the Author: Edward P. Mahaffy, MBA, CFP®, ChFC® is co-founder of Fiduciary Wealth Management. He founded his own firm, ClientFirst Wealth Management, LLC., in 2007 after more than 23 years in the wealth management industry. Contact him at ed@clientfirstwm.com.

 

Thanks to the Sponsors of Today's CPA Magazine

This content was made possible by the sponsors of this issue of Today's CPA Magazine:

8amCPACharge

Accounting Biz Brokers

Accounting Practice Sales

Goodman Financial

Paychex

TXCPA Member Insurance

 



  • TXCPA Strategic Plan

    Building What’s Next: TXCPA’s 2025-26 Year in Review

    TXCPA’s 2025–26 Year in Review highlights how the organization is responding to rapid change in the accounting profession through a clear strategic vision focused on people, innovation and advocacy. Key efforts include new programs, enhanced CPE and learning through AcctoFi, and technology and chapter integration initiatives. The year also marked major legislative wins, positioning Texas as a national leader.
    View Article
  • CPE: Option-Based Contracts and Foreign Currency Transactions

    This article covers option-based contracts in foreign currency transactions and their treatment as derivatives under ASC 815. It highlights how options differ from forwards and futures, outlines call and put options and their accounting implications, defines key derivative terminology, and illustrates how FX options can hedge one-sided currency risk while preserving upside potential.
    View Article
    Underlyings
  • volunteer leadership

    Celebrating Progress. Shaping What’s Next.

    This issue of Today’s CPA reflects on TXCPA’s achievements during the 2025–2026 membership year while looking ahead to the future. It highlights advocacy successes, profession updates, expanded education offerings, technology investments, and strong member and volunteer engagement. As the year closes, members are encouraged to stay engaged and help shape what’s next.
    View Article
  • CARB vs. No-CARB – The California Climate Accountability Package

    California’s Climate Accountability Package significantly expands corporate climate disclosure requirements, mandating detailed greenhouse gas emissions reporting and climate‑risk analysis for companies doing business in the state. Ongoing legal challenges remain, but enforcement timelines are intact, placing growing responsibility on companies and CPAs to manage data quality, Scope 3 estimates and audit‑ready disclosures.
    View Article
    Scope 1, 2 and 3 emissions
  • Pro Bono Services

    Justice for Fraud Victims Project: Bridging the Justice Gap in Financial Fraud

    The Justice for Fraud Victims Project (JFVP) is a national program that delivers free forensic accounting and fraud investigation services to vulnerable individuals, small businesses and nonprofits. With partnerships among universities, anti-fraud professionals and law enforcement, they help uncover financial crimes and educate future forensic accountants. The model is expanding, including a new program at Lubbock Christian University.
    View Article
  • A Refresher on Auditor Independence: Best Practices Every CPA Should Know

    Auditor independence is essential to maintaining trust in the accounting profession, requiring both objectivity and the appearance of impartiality. Common threats - such as self-interest, self-review and familiarity - continue to lead to violations. Strong firm policies, ongoing training and effective use of technology are key to preventing these issues.
    View Article
    Quality Control Systems
  • Tax‑Exempt Securities

    Are Municipal Bond Investors Sitting on a Ticking Tax Bomb?

    Tax‑exempt municipal bonds purchased at deep discounts can quietly trigger ordinary income taxation under the IRS de minimis rule, eroding after‑tax returns and creating surprise tax bills at maturity. By comparing after‑tax “true yield” and proactively swapping discounted bonds for higher‑coupon alternatives, CPAs and financial advisors can help clients defuse a hidden tax bomb and improve portfolio outcomes.
    View Article
  • Risks, Realities and the Evolving Role of CPAs Auditing Emerging Technologies

    Emerging technologies are reshaping auditing by embedding automation, advanced analytics and decentralized systems into core business processes. While these tools improve efficiency and insight, they introduce new risks that challenge traditional audit approaches. CPAs must adapt methods, rely more heavily on professional judgment, and uphold independence and integrity to sustain trust in financial reporting.
    View Article
    Quantum Computing
  • volunteer advocacy

    What’s Happening Around Texas - May-June 2026

    TXCPA chapters across Texas are making an impact through service, networking and professional development. Recent highlights include volunteer and scholarship efforts in Austin, community engagement and member meetups in Dallas, student outreach and advocacy in East Texas, and career-focused events in Houston that strengthen connections within the accounting community.
    View Article
  • Advocacy Update – Elections and the 2027 Legislative Session are Right Around the Corner

    TXCPA is preparing for the 2027 Texas legislative session as the 2026 elections shape the political and policy landscape. Key focuses include monitoring election outcomes, emerging legislative issues and national deregulation efforts that could impact CPA licensure and practice, while encouraging continued member engagement and advocacy.
    View Article
    volunteer leadership
  • Service differentiation

    Why Positioning Matters More Than Ever for CAS Firms

    Client advisory services deliver the most value when firms clearly define who they serve and which problems they solve. Clear positioning enables standardized workflows, repeatable service offerings and more predictable growth.
    View Article
  • Take Note

    In this edition of Take Note: Renew Your TXCPA Membership; Accountants Confidential Assistance Network (ACAN); 2026 CPE Programs; Word Game - Positioning That Powers Growth
    View Article
    Word Challenge
  • Classifieds

    The Classifieds section of Today's CPA provides a one-stop destination to find practices for sale, connect with buyers, and access services that support growth, transition and market expansion.
    View Article

CHAIR
Mohan Kuruvilla, Ph.D., CPA

PRESIDENT/CEO
Jodi Ann Ray, CAE, CCE, IOM

CHIEF OPERATING OFFICER
Melinda Bentley, CAE

EDITORIAL BOARD CHAIR
Jennifer Johnson, CPA

MANAGER, MARKETING AND COMMUNICATIONS
Peggy Foley
pfoley@tx.cpa

MANAGING EDITOR
DeLynn Deakins
ddeakins@tx.cpa

COLUMN EDITOR
Don Carpenter, MSAcc/CPA

DIGITAL MARKETING SPECIALIST
Wayne Hardin, CDMP, PCM®

CLASSIFIEDS
DeLynn Deakins

Texas Society of CPAs
14131 Midway Rd., Suite 850
Addison, TX 75001
972-687-8550
ddeakins@tx.cpa

 

Editorial Board
Derrick Bonyuet-Lee, CPA-Austin;
Aaron Borden, CPA-Dallas;
Don Carpenter, CPA-Central Texas;
Rhonda Fronk, CPA-Houston;
Aaron Harris, CPA-Dallas;
Baria Jaroudi, CPA-Houston;
Elle Kathryn Johnson, CPA-Houston;
Jennifer Johnson, CPA-Dallas;
Lucas LaChance, CPA-Dallas, CIA;
Nicholas Larson, CPA-Fort Worth;
Anne-Marie Lelkes, CPA-Corpus Christi;
Bryan Morgan, Jr, CPA-Austin;
Stephanie Morgan, CPA-East Texas;
Kamala Raghavan, CPA-Houston;
Amber Louise Rourke, CPA-Brazos Valley;
Shilpa Boggram Sathyamurthy, CPA-Houston, CA
Nikki Lee Shoemaker, CPA-East Texas, CGMA;
Natasha Winn, CPA-Houston.

CONTRIBUTORS
Melinda Bentley; Kenneth Besserman; Kristie Estrada; Holly McCauley; Craig Nauta; Kari Owen; John Ross; Lani Shepherd; April Twaddle; Patty Wyatt