# How do zero-coupon bonds work?

# Understanding How Zero-Coupon Bonds Work

Zero-coupon bonds are unique investment instruments that do not make periodic interest payments like traditional bonds. Rather, they are issued at discount to their face value, and at maturity, the investor receives the face value. The earnings for the investor is the difference between the purchase price and the face value. Below, we will delve deeper into the workings of zero-coupon bonds.

## Concept of Zero-Coupon Bonds

Before understanding how zero-coupon bonds work, it is crucial to understand what they are. A zero-coupon bond, also known as an “accrual bond” or “deep discount bond,” doesn’t pay interest (coupon) periodically. Instead, it pays its compound interest at maturity along with the face value of the bond. The interest is effectively rolled up to maturity, where it compounds semi-annually, annually, or at another set interval until the bond’s maturity date. The initial price of the zero-coupon bond is typically lower than the face value, hence the name “discount bond”.

## Purchasing Zero-Coupon Bonds

If an investor purchases a zero-coupon bond, they buy it at a substantial discount from its face value. The face value is the amount the issuer will pay the bondholder when the bond matures. For instance, a bond with a face value of $1000 might be available for purchase today at a price of $600. The difference of $400 is the investor’s earnings or interest at maturity – this is known as capital appreciation.

## Earning Interest

Zero-coupon bonds, contrary to their name, do actually earn interest. The way they do it, though, is fundamentally different from other types of bonds. For most bonds, the interest earned gets paid out periodically to investors in increments until the bond matures. On the other hand, zero-coupon bonds effectively reinvest the interest automatically and it compound until the maturity date. Therefore, an investor does not receive a periodic cash flow but instead a lump sum at maturity. This interest-compounding mechanism can lead to substantial returns over time.

## Understanding Risks Associated with Zero-Coupon Bonds

Like all financial instruments, zero-coupon bonds come with their own risks. For one, they have a longer duration, meaning they are more sensitive to interest rate changes. If rates rise, the value of the zero-coupon bond will drop more compared to a similar coupon-bearing bond due to the bond’s longer duration.

Furthermore, there is reinvestment risk. While zero-coupon bonds do not pay coupons and thus do not have reinvestment risk in the traditional sense, they have a hidden form of it. When market interest rates increase, bonds that were seen as desirable because of their high coupon rates become less appreciated and the prices of such bonds will decline.

On the other hand, during times of declining interest rates, zero-coupon bonds will gain value much faster due to their longer duration, providing a capital gain opportunity for the investor.

## Zero-Coupon Bonds at Tax Time

In many countries, zero-coupon bonds generate what is termed “phantom income,” or imputed interest, that is subject to tax. The authorities see the difference between the discounted purchase price and the full face value as interest income, even though the investor doesn’t receive any cash until the bond matures. Hence, the tax implications can be significant, and it is crucial for potential investors to understand the tax requirements in their specific country to avoid any unpleasant surprises.

## Conclusion: Power of Compounding in Zero-Coupon Bonds

Zero-coupon bonds can prove to be a valuable tool when utilized correctly, despite their complexities. They can be included in a portfolio’s fixed-income layers, particularly for tax-sheltered accounts or investors seeking a specific amount at a future date without needing interim cash flow.

The power of compounding in zero-coupon bonds comes from the fact that the interest is automatically reinvested at a known yield rate, i.e., the yield to maturity of the bond. This feature makes them an attractive investment choice for those who wish their money to grow measurably and are willing to invest for a longer time horizon. Remember, it is critical to understand the unique characteristics, tax implications, and inherent risks before investing in zero-coupon bonds.