Why a country's currency can suddenly collapse

HostWe carry these bits of paper and plastic in our wallets every day and we don't really think twice about them. We just trust that a ten dollar bill will buy us ten dollars of stuff tomorrow, but in some places, that trust just snaps. How does a whole country's money go from being solid to almost worthless in just a few days?

GuestIt helps to think about what that money actually is at its heart. It's a promise. It's a piece of paper that says the government will let you pay your taxes with it, and that other people will take it for bread or shoes. But that promise only works if everyone keeps believing in it. If I think you'll take this paper for a loaf of bread, I'll work to earn that paper. The moment I start to doubt that you'll take it, I don't want the paper anymore. I want to trade it for something real, like gold or even just a different kind of money from another country. When millions of people feel that doubt at the same time, they all try to get rid of their money at once. That's when the floor falls out.

HostBut there's usually a government in charge of the whole thing. Is there not a way they can just step in and say, look, this money is still worth what it was yesterday?

GuestThey try, and actually, that's often what leads to the biggest crashes. A lot of countries try to lock the value of their money to something they see as more stable, like the US dollar. They tell the world that four of their coins will always be worth one dollar. To keep that promise, the government has to keep a huge stash of actual US dollars in a vault. If people start selling the local money because they're scared, the government uses its stash of dollars to buy it all back. They're trying to prop up the price by being the biggest buyer in the room. The problem is that vault isn't bottomless.

HostSo what happens when they run out of the good stuff?

GuestThat's the breaking point. People who watch these things for a living start to see the vault getting empty. They realize the government is running out of ways to fight back. They think, if I don't trade my local money for dollars now, there will be no dollars left in the vault to trade with tomorrow. So they rush to the bank. It turns into a race. The government is trying to hold the door shut, but the weight of everyone pushing on it's just too much. Eventually, they have to let go. They announce that they can't keep the price locked anymore. The second they say that, the price doesn't just dip, it plunges. It falls to what it's actually worth without the government propping it up.

HostIt's the speed of it that's so hard to wrap my head around. We're talking about the wealth of an entire nation. Can that really just vanish over a weekend?

GuestWell, money moves a lot faster than it used to. It's not just people standing in line at a bank window anymore. It's big funds and banks moving billions with a click of a button. They see a country is in trouble, and they want out immediately. But there's also a bad loop that starts to happen. As the price of the money drops, the things that country buys from the rest of the world, like gas or food, suddenly cost way more. If your money is worth half what it was yesterday, a gallon of gas from another country now costs you twice as much. To pay for that, the government might just print more money. But adding more paper to the pile just makes each piece of paper worth even less. You're printing more to pay for things, but the printing is what's killing the value.

HostBut the country still has its factories and its farms. Surely the real stuff they make is still worth something?

GuestThe buildings are still there and the crops are still growing, but the gears of the economy need that money to turn. If you own a factory and you need to buy parts from overseas, and your money just crashed, you can't afford those parts. You might have to stop work. Then your workers don't get paid, so they can't buy food. Even if the farm next door has plenty of food, the farmer might not want to sell it for money that's losing value every hour. They might just keep the grain in the silo and wait for things to settle. So even though the real stuff is still there, the system that moves it around breaks. The money was the oil in the engine, and suddenly that oil has turned to sand.

HostSo it's basically a mass panic where everyone is watching to see who runs for the exit first.

GuestThe most fragile thing in any bank isn't the gold or the cash, but the belief that you can get it back whenever you want.

HostThat bit of paper in my pocket is only worth something because I know you believe in it as much as I do.