This is both true and false: a fall in the price of a bond reflects opportunity costs. An example: you buy a brand-new MacBook Pro (bond) today for $1800. The n

This is both true and false: a fall in the price of a bond reflects opportunity costs. An example: you buy a brand-new MacBook Pro (bond) today for $1800. The next day, Apple cuts the price of the exact same model by 30% to $1260 (interest rates rise, bond prices falls). On the one hand, you have exactly the same computer you had on the previous day (same stream of interest payments), so you could say that you haven't lost anything. On the other hand, if you'd waited a day, you could have gotten exactly the same thing for $540 less, so you could say that you're out that amount. And if you fall on hard times and need to sell the computer, no one will be willing to pay you $1800 for it, since they can buy it from Apple for much less, so in that case the opportunity cost becomes an explicit cost.