Zero-Coupon Bond

A zero-coupon bond is a debt security that makes no periodic coupon payments. Instead, it is issued at a steep discount to its face value and redeemed at full value at maturity, with the entire return coming from the discount. Zero-coupon bonds are common among Treasury securities (Treasury bills, STRIPS), corporate issuers, and investment funds.

The mechanics: discount and compound growth

A zero-coupon bond maturing in 10 years with a $1,000 face value might be purchased for $400. The $600 difference between the $400 purchase price and the $1,000 redemption value is the investor’s return, realized entirely at maturity.

This $600 return compounds over 10 years. To calculate the annual return: ($1,000 ÷ $400)^(1/10) - 1 ≈ 9.9% per year. The investor earns approximately 9.9% annually, compounding, with no interim coupon payments.

This compounding creates powerful long-term growth. An investor with a 20-year zero-coupon bond at 5% annual return will see their investment nearly triple. The longer the maturity, the more compounding contributes to total return.

Why zero-coupon bonds exist

Zero-coupon bonds serve several purposes:

Simplicity for Treasury — The Treasury issues zero-coupon Treasury securities (Treasury bills) because they are simple to administer and investors understand them intuitively.

Tax efficiency (in some cases) — Some investors, particularly those in tax-deferred accounts (IRAs, 401(k)s), prefer zero-coupon bonds because all return is realized at maturity, avoiding interim tax bills.

Price appreciation for capital appreciation investors — Investors seeking price appreciation rather than income can buy zero-coupon bonds, realizing the full return as capital gains.

Immunization matching — Pension funds and insurance companies with specific future obligations can buy zero-coupon bonds maturing on exactly the date funds are needed, perfectly matching liabilities.

Tax complications in taxable accounts

Zero-coupon bonds create a major tax problem in taxable accounts: the bondholder must pay annual federal income tax on the accrued interest (the growth in the bond’s value) even though no cash is received until maturity.

An investor buying a zero-coupon bond for $400 might have accrued interest of $60 in year one. The bondholder must report that $60 as income and pay taxes on it — even though they received no cash. Over 10 years, this “phantom income” accumulates to $600, and the investor has paid taxes on all of it before receiving any money from the bond.

This makes zero-coupon bonds unsuitable for taxable accounts unless the investor expects low income in future years or other offsetting losses. They are far more appropriate in tax-deferred accounts where no annual taxes are owed.

Extreme interest-rate sensitivity

Zero-coupon bonds have the longest possible duration for their maturity. A 10-year zero-coupon bond has a duration of approximately 10 years; a 10-year coupon bond has a duration of approximately 7–8 years.

This extreme duration means zero-coupon bonds are extraordinarily sensitive to interest-rate changes. A 1% rise in rates causes a 10% price decline in a 10-year zero-coupon bond. A 1% fall causes a 10% price appreciation. This volatility is the flip side of the long-term compounding — the bonds are leveraged plays on interest rates.

For buy-and-hold investors with long time horizons, this volatility is irrelevant (the bond matures at par). For investors who might need to sell before maturity, the volatility is meaningful — they could face significant losses in a rising-rate environment.

STRIPS and Treasury zeros

The Treasury issues zero-coupon securities through a program called STRIPS (Separate Trading of Registered Interest and Principal of Securities). Dealers buy ordinary Treasury notes and bonds, separate the principal and coupon payments, and sell them as individual zero-coupon securities.

A 10-year Treasury note with 20 coupon payments can be separated into 21 STRIPS: one principal payment (the “zero”) due in 10 years, and 20 coupon payments due semi-annually. Investors can buy any of these individual STRIPS, creating synthetic zero-coupon securities.

STRIPS are identical to corporate zero-coupon bonds in structure but have the credit quality of Treasury securities.

Corporate zero-coupon bonds

Corporations sometimes issue zero-coupon bonds, particularly distressed issuers or start-ups. A zero-coupon bond is attractive to an issuer with weak cash flow (because no interim coupon payments are required) but unattractive to investors (who must reinvest or endure no income).

The higher duration risk and lack of interim cash flow make corporate zero-coupon bonds appropriate only for investors with strong risk tolerance and long time horizons.

Valuation and trading

A zero-coupon bond’s value is simply the present value of the single future cash flow (the face value at maturity). If a 10-year zero-coupon bond with a $1,000 face value is trading at a 5% yield, its price is $1,000 ÷ (1.05)^10 ≈ $614.

Zero-coupon bonds trade less frequently than coupon bonds, but their prices can be easily calculated from the yield and maturity date.

See also