It's just rent. For money.
Strip the jargon and an interest rate is stupidly simple: it's the price of borrowing money. You borrow, you pay it back — plus a fee for using it. That fee is interest.
Think renting an apartment. You don't own it, you want to use it, you pay rent. Borrowing money is the same deal. Rent, but for money.
One interest rate bosses all the others around: the rate set by central banks. In Europe, the ECB. In the US, the Fed. They set the base rate — the master dial — and every other rate follows. Your mortgage, car loans, your savings account. All of it.
Think of it as the thermostat of the economy. Rates low, the room's warm — borrowing's cheap, people spend, everyone's cozy. But too warm too long and things overheat: prices rise faster than wages. That's inflation. So the central bank cranks the thermostat down.
Bonds, stocks, and your future apartment
Three ways rising rates hit markets — from abstract to very-much-your-problem.
Bonds. A bond is an IOU — you lend money, they pay you interest, you get it back at the end. When rates rise, new bonds pay more, which makes the old ones look worse, so their price drops. Rates up, bond prices down. Feels backwards at first. Then it clicks and you feel like a genius.
Stocks. Two hits at once. First: companies pay more on their debt, profits shrink, stock prices fall. Second — the sneaky one — when a risk-free bond suddenly pays 4%, why take on the risk of the stock market? Investors pull money out and park it somewhere safe. That wave of selling drags prices down further.
Your actual life. Someone wants to buy a €300,000 flat in Vienna. Here's the monthly payment on a 30-year loan:
That's €467 more every single month. Over 30 years: roughly €168,000 in extra payments. For the identical apartment — because a central banker nudged one number.
You've got €1,000. A savings account offers 4% — guaranteed, no risk. Do you take the safe 4%, or still throw it into stocks? Most people reach past the guaranteed return for the bigger maybe. That instinct has a name: return chasing. It trips up Wall Street pros as often as beginners.
2022 — the year it all broke
Post-COVID, inflation was running wild. Central banks had held rates near zero through the pandemic, but prices were spiralling. So they slammed the brakes — hard.
The S&P 500 — the 500 biggest US companies — fell about 18% that year. Painful, but not unusual. The insane part: bonds fell too, around 13%. The worst year for bonds in modern history. Bonds are supposed to be the safety net — when stocks fall, bonds catch you. In 2022, both crashed together. A standard stock-and-bond portfolio had its worst year since 1937. Nowhere to hide.
Meta lost around 237 billion dollars of value in a single day — the biggest one-day wipeout in US market history at the time. Peak to bottom, Meta fell around 76%. Netflix was down roughly 62% on the year — the single worst stock in the S&P 500.
Why tech specifically? Tech companies aren't priced on what they earn today — they're priced on what they'll earn way out in the future. And there's a rule: money in the future is worth less than money today. When rates are high, future money is worth even less. It's called discounting.
High rates shrink all those far-off profits. So investors redid the math, decided those future billions weren't worth what they thought, and sold. One dial — zero to four percent — and trillions of dollars repriced.
Low rates aren't free either
Everyone treats high rates like the villain. But the 2010s showed the other side. Rates near zero, money flooded into everything — stocks, real estate, crypto went feral. Everything felt like it only went up. And that feeling is historically one of the most reliable signs a crash is loading.
Meanwhile, if you were responsible — money sitting safe in a savings account — you got punished. Banks paid basically nothing while inflation quietly ate your balance. You did the smart thing and lost real value for it.
So central banks are forever hunting the sweet spot. And honestly? They don't always find it.
- Interest rates are the price of borrowing money — and one rate set by central banks controls all the others.
- When rates rise, borrowing gets expensive, stock prices fall, and tech gets hit hardest because future profits are worth less today.
- Low rates aren't free either — they pump everything up and punish people doing the boring, smart thing.