Debt Securities·Municipal

Municipal Bonds

General Obligation (GO) Bonds

General Obligation bonds are municipal bonds backed by the full faith, credit, and taxing power of the issuing government entity (state, county, city, or school district). When an issuer cannot meet debt payments, it can raise taxes to cover the obligation — which is what makes GO bonds among the safest category of municipal debt.

Voter approval is required before a municipality can issue GO bonds, because the bond pledges the taxing power of the issuer and ultimately obligates taxpayers. This democratic check limits supply and contributes to GO bonds' lower yields compared to revenue bonds.

Unlimited tax GO bonds can raise taxes without a statutory cap. Limited tax GO bonds are backed by taxing power constrained to a specific maximum rate — slightly riskier than unlimited tax bonds.

Analogy: A GO bond is like borrowing money and putting your salary as collateral. Your lender knows you have the power to earn income (tax) to repay, which makes the loan safer than a business venture loan with no guaranteed income stream.

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Revenue Bonds

Revenue bonds are repaid solely from the revenues generated by the specific project they finance — a toll road, bridge, airport, water utility, hospital, or sports stadium. They carry no pledge of taxing power, so if the project generates insufficient revenue, bondholders may not be repaid.

Because of this additional risk, revenue bonds typically offer higher yields than comparable GO bonds. The bond's indenture includes protective covenants such as:

  • Rate covenant: Issuer must keep fees high enough to cover debt service
  • Maintenance covenant: Issuer must maintain the facility
  • Additional bonds test: Before issuing more debt, existing revenues must exceed a coverage threshold
  • Net revenue pledge: Debt service paid from revenues after operating expenses (most common for utilities). Gross revenue pledge: Debt service paid before operating expenses — stronger for bondholders, less common.

    Revenue bonds do not require voter approval because they do not pledge taxpayer money.

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    Tax Treatment of Municipal Bonds

    Municipal bond interest is treated specially under the tax code:

  • Always exempt from federal income tax — regardless of the investor's state of residence
  • Exempt from state and local taxes only in the state where the bond is issued (in-state bonds). An investor in California buying a California muni pays no CA state tax on interest, but a New York investor buying that same California bond pays NY state tax on the interest.
  • NOT exempt from federal estate tax — municipal bonds are included in the taxable estate at death
  • Alternative Minimum Tax (AMT): Certain "private activity bonds" (like some IDBs) generate interest that is a preference item for AMT purposes — high-income investors may owe AMT on this interest even though it is technically "exempt"
  • The combination of federal tax exemption and high marginal tax rates makes munis especially valuable to investors in the 32%, 35%, or 37% federal brackets.

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    Tax-Equivalent Yield (TEY) Formula

    The TEY tells an investor what a taxable bond would need to yield to match the after-tax return of a tax-exempt municipal bond.

    Formula: TEY = Muni Yield / (1 - Investor's Marginal Tax Rate)

    Example: A muni bond yields 4.0%. The investor is in the 35% federal tax bracket. TEY = 4.0% / (1 - 0.35) = 4.0% / 0.65 = 6.15%

    This means the investor would need to earn 6.15% on a taxable bond to match the after-tax value of the 4.0% muni. If a corporate bond yields 5.8%, the muni is the better after-tax choice. If the corporate yields 6.5%, the corporate wins.

    Key insight: TEY rises as the tax bracket rises. A muni yielding 4% is worth 5.71% TEY to a 30% bracket investor but 6.67% TEY to a 40% bracket investor — making munis progressively more attractive to higher earners.

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    Industrial Development Bonds (IDBs)

    IDBs are issued by a municipality on behalf of a private company to finance industrial or commercial projects (factories, warehouses, stadiums). The municipality acts as a conduit — the bonds are technically municipal securities, but the obligation to repay rests entirely on the private corporation, not the municipality.

    Tax treatment: IDBs issued for private purposes may generate interest that is a preference item for AMT. Some IDBs are fully taxable. Exam questions often test whether the interest is truly tax-exempt or subject to AMT.

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    Double-Barreled Bonds

    Double-barreled bonds are secured by both a specific revenue source AND the general taxing power of the issuer. They offer the strongest repayment security among municipal bonds, combining revenue stream protection with a GO backstop.

    Example: A water utility bond backed by water revenues as primary repayment, with the city's taxing power as a secondary guarantee.

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    Municipal Bond Insurance

    Private insurers like AMBAC and MBIA (now largely restructured post-2008) provide guarantees that bond principal and interest will be paid even if the issuer defaults. Insured bonds receive the insurer's credit rating (historically AAA), which lowers yield requirements and thus reduces borrowing costs for lower-rated municipalities. After the 2008 financial crisis, many insurers were downgraded, reducing the practical benefit of insurance.

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    Special Assessment Bonds

    Special assessment bonds are repaid by assessments levied on property owners who directly benefit from the improvement being financed (a new sewer line, sidewalk, or streetlight project). Only the benefiting property owners are assessed — not all taxpayers. They are considered a form of limited obligation bond.

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    Short-Term Municipal Instruments

  • BANs (Bond Anticipation Notes): Interim financing issued while waiting to issue long-term bonds
  • TANs (Tax Anticipation Notes): Issued in anticipation of future tax revenues (e.g., before property tax collection)
  • RANs (Revenue Anticipation Notes): Issued in anticipation of future revenue receipts (grants, fees)
  • CLNs (Construction Loan Notes): Issued to fund construction before permanent financing
  • All are short-term (typically under 1 year) and are repaid when the anticipated funds arrive.

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    Key Terms

  • General Obligation bond: Backed by taxing power of the issuer; voter approval required
  • Revenue bond: Backed only by project revenues; no voter approval required
  • Tax-equivalent yield (TEY): Taxable yield needed to match a muni's after-tax return
  • Double-barreled bond: Backed by both revenue and taxing power
  • Industrial Development Bond (IDB): Muni conduit for private corporate financing; may be AMT-affected
  • Special assessment bond: Repaid by assessments on benefiting property owners
  • Net revenue pledge: Debt service paid after operating costs
  • Gross revenue pledge: Debt service paid before operating costs
  • BAN/TAN/RAN/CLN: Short-term notes anticipating future bond proceeds, taxes, revenues, or construction loan takeouts

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Quiz Questions:

Q1. A municipal bond yields 3.5%. An investor is in the 37% federal tax bracket. What is the tax-equivalent yield?

A) 4.78% B) 5.26% C) 5.56% D) 6.25%

Answer: C — TEY = 3.5% / (1 - 0.37) = 3.5% / 0.63 = 5.56%. Answer A uses (1 - 0.27), Answer B uses an incorrect divisor, and Answer D uses an incorrect divisor of 0.56. The exam will often provide the bracket and require the calculation from scratch.

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Q2. Which of the following statements about General Obligation bonds is CORRECT?

A) They are backed only by revenues from a specific project B) They require voter approval before issuance C) They do not pledge the taxing power of the issuer D) They typically offer higher yields than comparable revenue bonds

Answer: B — GO bonds pledge the taxing power of the municipality and therefore require voter approval since taxpayers are ultimately obligated. A describes revenue bonds. C is incorrect — GO bonds do pledge taxing power. D is backward — GO bonds are safer and thus yield less than comparable revenue bonds.

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Q3. A New York resident purchases a California municipal bond. Which of the following correctly describes the tax treatment of the interest?

A) Exempt from both federal and New York state income tax B) Exempt from federal income tax but subject to New York state income tax C) Subject to both federal and New York state income tax D) Exempt from federal, state, and estate taxes

Answer: B — Municipal bond interest is always exempt from federal income tax. However, the state exemption applies only in the issuing state. A New York investor buying a California bond still owes NY state income tax on that interest. D is wrong because munis are NOT exempt from federal estate tax.

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Q4. A revenue bond issued to finance a toll bridge includes a covenant requiring that toll revenues always exceed 1.25x annual debt service before new bonds can be issued. This is best described as:

A) A rate covenant B) An additional bonds test C) A maintenance covenant D) A gross revenue pledge

Answer: B — An additional bonds test specifies the minimum revenue coverage ratio the issuer must meet before issuing more bonds on parity. A rate covenant requires the issuer to set fees high enough to cover current debt service. A maintenance covenant requires upkeep of the project. A gross revenue pledge prioritizes debt service before operating expenses — not what is described here.

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Q5. Which of the following short-term municipal instruments is issued to finance construction costs while long-term permanent financing is being arranged?

A) Tax Anticipation Note (TAN) B) Revenue Anticipation Note (RAN) C) Bond Anticipation Note (BAN) D) Construction Loan Note (CLN)

Answer: D — CLNs are specifically issued to fund construction in advance of permanent financing. BANs (C) are issued while waiting to complete a permanent bond offering but are not specific to the construction phase. TANs (A) anticipate tax collections. RANs (B) anticipate revenue receipts. The distinction is that CLNs are tied to the construction activity itself.