An intriguing contrarian play is long-term bonds maturing in 20 to 30 years.

There are few fans of the sector, and the negatives are many. They include intractable federal budget deficits, inflation around 3%, and heavy corporate borrowing for data centers to fuel the artificial intelligence boom.

Losses have accelerated recently as the yield on the 30-year Treasury has risen almost a half percentage point to 5.6% in the past month.

Bond maven Dan Fuss, 93, who formerly headed the Loomis Sayles Income fund, told Barron's recently it would "take a team of oxen to make me buy a 20-year bond." BlackRock urged investors to underweight long-term Treasuries, citing "persistent inflation and high debt loads."

Fuss argues investors should buy intermediate-term debt-he favors five to seven-year maturities-because it offers nearly as much yield as long-term bonds with less risk. BlackRock favors agency mortgage securities that now yield over 6%.

But there are good reasons to consider long bonds.

Barron's recently highlighted the appeal of 30-year munis yielding over 5%.

There also is a case for long-term Treasury bonds, long Treasury zero-coupon debt, long-term Treasury inflation-protected securities, or TIPS, and long-term corporate bonds. These securities are better suited to tax-advantaged accounts like IRAs, while munis belong in taxable accounts.

Yields now are at 20-year highs, with 20-year and 30-year Treasuries yielding about 5.6%. That yield could prove competitive with stocks over the long term and is safe, although there is the risk that returns will be eroded by inflation.

"This is one of the best entry points for long-term bonds we've seen in nearly two decades. Starting yields are one of the best predictors of forward returns in fixed income," says Gene Goldman, chief investment office at Cetera Financial Group.

Long-term bonds could offer competitive returns if equity market returns cool. There is no law that says stocks should return 10%-plus annually, as they have done for the past 10 and 30 years. Historically, there are decadelong periods of poor equity returns. That's especially true with the U.S. stock market valued at over $70 trillion.

Long Treasuries also could offer a hedge against stocks if the economy weakens-effectively a put option on the S&P 500 index yield.

There is risk. Bond prices move inversely with yields and long-term debt gets hit hardest when market rates increase. The $47 billion iShares Treasury 20+Year Treasury Bond exchange-trade fund is down more than 10% this quarter.

Investors can directly buy individual Treasury bonds and TIPS from the Treasury at regular auctions at Treasury.gov and through brokerage firms and banks.

Investors need to buy Treasury zero-coupon and corporate bonds through banks and brokerage firms like Fidelity and Morgan Stanley.

A good alternative to individual bonds are low-cost exchange traded funds. Here are four ETFs worth considering.

The iShares 20+ Year Treasury Bond ETF has an average maturity of 26 years, with a current yield of 5.4% The Pimco 15+ Year U.S. TIPS Index ETF has a maturity of 22 years.

The Pimco 25+ Year Zero Coupon U.S. Treasury Index ETF has a maturity of close to 28 years and a 5.5% yield, and the Vanguard Long-Term Corporate Bond ETF has a 22-year average maturity and yield of 6.2%.

The Vanguard ETF holds investment-grade debt-mostly triple-B and single-A-and yields 6.2%, almost a percentage higher than the TLT Treasury ETF.

Treasury strips also have their attributes.

A buyer of Treasury zero-coupon bonds, or strips, receives no cash interest. The interest gets paid at maturity, although investors are free to sell them before that. They are called strips because bond dealers take a Treasury 30-year bond and strip it into the component parts:-60 semiannual interest payments and the principal portion of the bond maturing in 30 years-and sell them separately.

A 30-year zero-coupon bond now yields about 5.5% and trades for about 20 cents on the dollar, meaning that an investor will see a fivefold increase in value over 30 years with no risk. Zeros allow investors to lock in a yield-unlike regular Treasuries, where the yield is dependent on investing interest payments at the stated yield.

There is rate risk with 30-year Treasuries, and especially with long-term zeros, but both have a nice feature: Returns are asymmetric in the investor's favor.

Zero-coupon bonds will rise in price more if rates fall than decline if rates increase, due to what bond pros call positive convexity. A 30-year Treasury should increase about 17% in price if rates fall one percentage point and drop 13% in price if rates rise one point based on Bloomberg data, and that drop will be partly offset by interest income. The risk/return on Treasury zeros is even better.

Unlike the underlying bonds in its portfolio, the Pimco 25+ Year Zero Coupon ETF pays interest from the periodic rebalancing of the portfolio. This helps investors pay taxes since they are taxed on the annual accreted interest on Treasury zeros.

TIPS could be the most appealing group of Treasuries since they protect investors from what they fear most-higher inflation.

They pay an inflation component tied to the U.S. consumer price index and a bonus, or real, rate above inflation. For 30-year TIPs, the real rate is now 3.3%, which is attractive historically. Essentially, investors are able to get a risk-free 3.3% return above inflation.

The current break-even inflation rate is only 2.3%. This means that if inflation runs above that rate-not a bad bet-investors will do better with TIPS than regular Treasuries. The break-even is calculated by subtracting the real TIPS yield from the Treasury 30-year bond yield.

Given high current rates, it might be smart now to buy that which has been most toxic-long-term bonds.