Recently, more and more people are looking for safe assets, and among them, U.S. Treasury bonds are a really attractive option. Because they start from the trust that the U.S. will never fail. Even if interest rates are low, you can convert them into cash at any time, and since interest is paid regularly, they seem like the best product for retirees.

First, I think I should talk about what bonds are. Simply put, it's the government asking to borrow money. In return, they promise to return the principal on a set date and pay interest in the meantime. U.S. Treasury bonds mainly come in three types. There are short-term bills (T-bills) under one year, medium-term notes (T-notes) from 1 to 10 years, and long-term bonds (T-bonds) from 10 to 30 years, with the most actively traded being the 10-year bonds.

Here, the important thing is the relationship between interest rates and yields, which move inversely. When more people want to buy Treasury bonds, their prices go up and interest rates fall. Conversely, if the demand drops, the opposite happens. So, bond yields can be seen as a direct reflection of investor sentiment.

The biggest advantage of U.S. Treasury bonds is their safety. Since the U.S. government guarantees them, the risk of default is almost zero. Also, a fixed interest rate is set at issuance, making returns predictable. Plus, they are highly liquid, so you can sell them at any time before maturity without waiting. From a tax perspective, only federal taxes are levied, while state and local taxes are exempt, which can result in a higher after-tax return than expected.

Of course, there are risks. If interest rates rise, existing bond prices fall, so you could incur losses if you sell before maturity. Inflation is also a concern because fixed interest rates may not keep up with rising prices. For foreign investors, currency fluctuations must also be considered, and theoretically, there's a very low chance that the U.S. government might default on its debt. But that possibility is extremely low.

There are three ways to buy U.S. Treasury bonds. The first is to buy directly. You can purchase directly from the U.S. government via the TreasuryDirect website or buy on the secondary market through a broker. The advantage is no intermediary fees and direct management, but the downside is you can only buy up to $10,000 at a time. Buying multiple bonds requires significant funds and management.

The second is to buy bond funds. These pool money from many investors and are managed by professionals with a diversified bond portfolio. They allow for small investments and easy management, but fees are charged, which can slightly reduce returns.

The third is to buy bond index funds or ETFs. These track specific government bond indices, have much lower fees than mutual funds, and can be bought and sold freely like stocks. The downside is that their prices can fluctuate with market movements.

For Korean investors, mixing Korean and U.S. Treasury bonds is a good idea. It allows diversification across regions and currencies, reducing risk. Especially, the ability to hedge against exchange rate fluctuations is attractive. Since Korea and the U.S. have different economic cycles, when one is weak, the other can support the portfolio.

From a yield perspective, if Korean bonds offer higher returns, you can allocate more to them, while maintaining U.S. Treasury bonds as a core position for stability. Large interest rate differences between the two countries can also create arbitrage opportunities.

The most important risk for Korean investors is exchange rate risk. Fluctuations in the dollar exchange rate can impact returns. You can hedge this risk with derivatives like forward contracts, locking in exchange rates, but that might prevent you from benefiting from favorable currency movements. Some investors hedge only part of their currency risk and leave the rest unhedged.

Duration is also important. It indicates a bond’s sensitivity to interest rate changes. If preservation of principal is the goal, buying long-term bonds makes sense. To reduce sensitivity to rate fluctuations, mixing in shorter-term bonds is advisable. Don’t forget taxes: U.S. Treasury interest is subject to federal tax, but Korea may also tax it. Fortunately, the U.S.-Korea tax treaty prevents double taxation.

A balanced portfolio of 50% Korean bonds and 50% U.S. Treasury bonds can aim for both principal preservation and income generation. It reduces risk by not relying solely on one country's economy. When the dollar is strong, the unhedged part of U.S. bonds can boost returns, and when it’s weak, the hedged part can offset losses.

Ultimately, investing in bonds (called Treasuries in English) requires a proper understanding of risks like interest rates, inflation, and exchange rates. For Korean investors, combining U.S. and Korean bonds can diversify the portfolio and enhance stability. Whether buying directly, through funds, or ETFs, choose a method suited to your situation and risk tolerance. Practicing with a demo account first is also a good idea.