What is a stablecoin? In plain words
A stablecoin is a token built to track a set value, usually a dollar. How reserves and a coat check keep USDC close to it, and why close is not fixed.
A payment of 100 dollars on Monday could be worth 92 dollars by Friday. Swings like that are normal for many crypto tokens, and they make those tokens awkward for rent, wages or a simple payment. So people built tokens that try not to move at all.
A token is a balance on a blockchain, a record kept on many computers at once. A stablecoin is a token built to track a set value, usually one dollar. The interesting question is how a line in a record can hold a price.
The coat check
Take USDC, one of the dollar tokens in wide use. Behind it stands a company that holds money called reserves, made up of cash and short loans to the government. Each USDC in use is matched by a dollar's worth of those reserves.
Picture a coat check beside a vault. A dollar crosses the counter, and a ticket is handed back: one USDC. Later the ticket is returned, and the dollar goes out again. The ticket is worth a dollar because of what it can be turned back into, not because of anything printed on it.
There is one detail that is easy to miss. That counter is not open to everyone. The company trades USDC for dollars one for one with approved businesses. Everyone else gets and sells USDC by trading with those businesses or with each other. So the price you see is a market price, set by people trading.
Why the price stays close
If the market sets the price, what keeps it near one dollar? Here is an example with made-up numbers.
Say USDC slips to 99 cents. An approved business can buy 1,000 USDC for 990 dollars, take it to the counter and get 1,000 dollars back. That is 10 dollars gained before costs. All that buying pushes the price back up.
Now say USDC rises to 1 dollar and 1 cent. The business can hand in 1,000 dollars, get 1,000 USDC and sell them for 1,010 dollars. All that selling pushes the price back down.
Nobody has to hold the price in place. The way back to a dollar gives traders a reason to step in whenever the price drifts. That is why the price of USDC usually stays near a dollar.
What people get wrong
"Stable means fixed." It does not. In March 2023, the price of USDC fell to about 87 cents for a short time. A bank holding part of the reserves had failed, and people were unsure that money could be reached. Within days, the price was back near one dollar. The ticket is only trusted while people believe the coat check can pay.
"All stablecoins work the same way." USDT and DAI also aim to track the dollar, and each does it in its own way. A few track other money, like the euro. The word stablecoin describes a goal, not a method.
"USDC is in one place." USDC exists on many chains, and each balance still lives on its own chain. USDC held on Base can be spent only there until it is moved.
How to read any stablecoin
Three questions show how a given stablecoin works. They do not tell you which one to hold.
- What is behind it, and who looks after that?
- Who, if anyone, can trade it back for what it tracks, and how?
- Is there a regular public report on what is held?
In short
- A stablecoin is a token built to track a set value, usually one dollar.
- USDC is backed by reserves of cash and short loans to the government.
- Approved businesses can trade it back one for one, and that pull usually keeps the price close to a dollar.
- A stablecoin is only as steady as what is behind it.
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