Woman smiling in library © Monkey Business Images/Shutterstock.com

Think that zero-coupon certificates of deposit mean zero risk?

Think again.

Zero-coupon CDs are bought at a deep discount, with interest accreting annually. At maturity, the CD pays out at a higher face value. For example, a $75,000 zero-coupon CD may be bought for, say, $50,000, and mature in 7 years. Interest is not paid annually but it is still treated as taxable income every year.

RATE SEARCH: Compare CD rates at Bankrate today.

But here’s where the risk comes in: These CDs lock in your money at lower rates, especially when interest rates look like they’ll rise, then interest is paid out years later.

Why? Because maturities can range from 3 to 30 years.

“Drawbacks loom large, especially when investors are reaching for higher yields,” says Greg McBride, CFA, senior vice president and chief financial analyst at Bankrate.com.

Drawbacks to zero-coupon CDs

Income is taxed yearly. Even though you don’t receive any interest until the CD matures, you must pay taxes on it each year. And if you opt for a hefty $100,000 CD, your tax hit can be big.

“Basically, you’re paying out of your own pocket for this phantom income, unless the CD is in a tax-advantaged retirement account,” McBride says.

Zero-coupon CDs may be callable. That means that it can be whisked away from you before it matures. This is usually true during times of falling interest rates, McBride says.

They provide no steady income. Retirees who need a yearly cash flow should look elsewhere.

“Ultimately, the CDs are aimed at extremely conservative investors with no cash-flow needs,” says Brad Levin, president of the wealth planning firm Legacy Wealth Partners in Woodland Hills, California.

Zero-coupon CDs are usually brokered. Good luck finding zero-coupon CDs at a bank, Levin says. They’re usually sold through a brokerage firm, which means you may pay extra fees. And be prepared to hang on for long maturities — as much as 15 to 20 years.

These CDs aren’t as liquid as you may think. Withdrawing money before a zero-coupon CD matures is no easy matter. You must sell it on a secondary market, where prices are driven by investor demand. That means you may lose money on your investment as CD values fluctuate.

Also, if interest rates rise, you’re stuck with a lower-yielding CD when other investment vehicles are yielding more. That’s why going with short-term, more liquid CDs is preferable to investing in longer-term CDs, McBride says.

Plus sides of zero-coupon CDs

Make no mistake, there are upsides, too. Zero-coupon CDs may pay higher yields than traditional CDs. For example, a 2-year zero-coupon CD might yield 2.4% compared to a traditional CD paying 1.5%, Levin says.

And you also know what rate you’re getting because the CD matures at a stated face value. Each year, that value grows as interest is added, until the CD reaches maturity. Another plus, says Levin, is that buying the CD at a substantial discount gives you bigger bang for your buck at maturity.

McBride says zero-coupon CDs are best suited to investors who are saving for long-term, targeted goals (such as buying a house).

Investors who don’t have hefty deposits should look at laddering traditional CDs instead, where you buy several different securities with different maturities, advises McBride. You can buy them with modest deposits.

RATE SEARCH: Ready to buy? Compare CD products on Bankrate.com now.