Why your 'safe' bond can lose money when rates rise

Bonds have a reputation as the boring, safe corner of investing — but they hide a counterintuitive trap. When interest rates go up, the market price of existing bonds goes down. This is the single most important rule in the bond world, and it surprises almost every beginner.

Here's the logic. Say you buy a bond that pays 3% a year. If new bonds start being issued at 5%, nobody wants your old 3% bond at full price anymore — they'd rather buy the new one. So to sell yours, you must discount its price until its effective return matches the 5% on offer. The bond didn't get riskier; the world around it simply changed.

The longer a bond's time until it matures, the more its price swings when rates move. This sensitivity is called duration — a 10-year bond falls much harder than a 2-year bond for the same rate change. That's why 'safe' long-term bonds can post real losses in a rising-rate year, as many investors painfully discovered in 2022.

The flip side is the good news: if you hold a bond to maturity, these price swings don't matter — you still collect your original interest and get your principal back. Price risk only bites if you need to sell early.