A crypto trader I know asked me why everyone on his feed panics when the 10-year yield ticks up. His portfolio was all tokens and tech stocks, not a single bond in it, and yet the days that hurt him most were bond market days. He knew the correlation was real because he could see it in his PnL. He just could not explain the mechanism, and honestly, most explanations he had read were hand-waving. Prices and yields move inversely, seesaw metaphor, moving on. So let me do the version with actual numbers, because once you see the arithmetic, the whole thing stops being mysterious and starts being useful.
A bond is just a fixed stream of cash. Say you buy a bond for 1,000 dollars that pays 40 dollars a year in coupons and gives you your 1,000 back in ten years. Those payments are printed on the contract. They never change. Not the coupon, not the principal, nothing. That fixedness is the entire story.
The used car lot problem
Now suppose market rates rise, and newly issued bonds of the same quality pay 50 dollars a year instead of 40. You decide to sell your bond. Who buys it? Nobody, at 1,000 dollars. Why would anyone pay full price for 40 dollars a year when the shop next door sells 50 dollars a year for the same money? Your bond is a used car sitting next to a newer model at the same sticker price.
The only lever you have is price. You cut it until the buyer's return matches what they could get elsewhere. Roughly speaking, the price has to fall to the point where 40 dollars a year, plus the gain from buying below 1,000 and getting 1,000 back at maturity, works out to about the same yield as the new bonds. For a ten year bond in this example, that lands somewhere around 920 dollars, give or take. The math is a discounted cash flow calculation, but the intuition is pure used car lot. Nothing about your bond got worse. The competition just got better, so your resale price dropped.
Run it in reverse and you get the other side. If new bonds start paying 30 dollars a year, your 40 dollar coupon is suddenly the attractive one, and buyers will pay above 1,000 for it. Yields down, prices up. There is no economics here, no sentiment, no story. It is arithmetic on fixed cash flows, which is why the relationship never breaks.
Duration is just the damage multiplier
The next question is how much the price moves, and that is where duration comes in. Duration gets taught as a scary formula, but you can hold the whole idea in one sentence. The longer you have to wait for your cash, the more a change in rates hurts you.
Compare two bonds when yields rise by one percentage point. A bond maturing in one year barely cares. You get your 1,000 back in twelve months and can reinvest at the new higher rate almost immediately, so the price only needs to drop a little, typically around one percent, to make the numbers work. A thirty year bond is a different animal. The buyer is locked into the old, now inferior coupon for three decades, so the price has to fall a lot to compensate, often in the range of fifteen to twenty percent for that same one point move. Same rate change, wildly different damage.
Duration is the number that summarizes this. A duration of 7 means, roughly, that a one percentage point rise in yields knocks about seven percent off the price. It is a first order approximation and it gets less accurate for big moves, but as a rule of thumb it is very serviceable. When someone says they are long duration, they mean they own assets whose cash flows sit far in the future, and they are exposed to exactly this multiplier.
- Rule of thumb: price change is approximately negative duration times the change in yield. Duration 7, yields up 0.5 points, expect roughly a 3.5 percent price drop.
- Longer maturity means higher duration. Lower coupons also mean higher duration, because more of your money arrives at the very end.
- The approximation understates gains and overstates losses slightly for large moves. Fine for sizing intuition, not fine for pricing derivatives.
Why your altcoin bag has duration
Here is the part that matters if you never intend to buy a bond. Any asset whose value depends on cash flows or payoffs far in the future is, mathematically, a long duration asset. A profitable utility company paying fat dividends today is short duration. A growth stock whose entire valuation rests on earnings a decade out is long duration. And a token whose bull case is adoption years from now, with essentially zero cash flow today, is about as long duration as an asset can get.
When the risk-free rate rises, every discounted cash flow model in the world reruns with a bigger denominator, and the assets with the most distant payoffs get marked down the hardest. This is the same arithmetic as the thirty year bond versus the one year bond. Nobody at the Fed is thinking about your altcoin, but your altcoin inherits the math anyway, because the risk-free rate is the benchmark everything else is priced against. It also shows up through collateral and leverage. Treasuries are the collateral backbone of traditional finance, and increasingly of crypto too through tokenized treasury products and stablecoin reserves. When bond prices fall, collateral values fall, and levered positions everywhere get a little tighter.
The practical takeaway is a habit, not a trade. Before I size any long-horizon position, I ask what happens to it if the 10-year yield moves up half a point, because history says moves of that size happen and I have watched them flatten portfolios that thought they had nothing to do with bonds. If most of your book is far-future payoff assets, you are effectively running one big duration bet whether you meant to or not, and diversifying across twelve different long duration tokens diversifies nothing. This is part of why we built macro benchmarks and rate context into the scorecards on Blockcircle, since crypto traders keep learning this correlation the expensive way.
The failure mode I see most is treating a yield spike as noise because you do not own bonds. You do not need to own bonds to be short them in spirit. If your assets promise their value in the distant future, rising yields are a direct repricing of your book, and the seesaw everyone hand-waves about is sitting under your positions right now. Better to know the multiplier before the move than after.