A stablecoin is a cryptocurrency designed to maintain a fixed value relative to a reference asset, usually the US dollar. One USDC or USDT is meant to always be worth $1. They exist because traders and DeFi users need a way to hold dollar-denominated value on-chain without converting back to traditional banking every time they want stability.
What Is a Stablecoin?
3 min read
The short version
Stablecoins are the dollars of the crypto world. Bitcoin and ETH swing in price constantly, which makes them great for speculation but terrible for paying rent or pricing a loan. Stablecoins solve this by staying pegged to $1, giving you a stable store of value that lives on the blockchain and moves as fast as any other crypto token.
How It Works
Three main categories: (1) Fiat-collateralized (USDC, USDT): a company holds real dollars (or Treasury bills) in bank accounts and issues one token per dollar held. Redeemable 1:1 through the issuer. (2) Crypto-collateralized (DAI): overcollateralized by crypto deposits. You deposit $150 of ETH to mint $100 of DAI. If ETH drops, you get liquidated to protect the peg. Decentralized, no single issuer. (3) Algorithmic (historical: UST/LUNA): used code-based mechanisms to expand/contract supply. Most have failed catastrophically (Terra/LUNA collapse, May 2022). The market has largely moved away from purely algorithmic designs. Market size: USDT ~$110B, USDC ~$35B, DAI ~$5B (as of mid-2024). Stablecoins settle more value annually than Visa and Mastercard combined, primarily for trading, remittances, and DeFi collateral.
Using USDC to lock in profits without leaving crypto
You bought 2 ETH at $2,000 each ($4,000 total). ETH rises to $3,500. You want to lock in the $3,000 profit without wiring money to your bank (which takes days and costs fees). You swap 1 ETH for 3,500 USDC on Uniswap. Now you hold: 1 ETH (still exposed to price movement) + 3,500 USDC (stable, locked-in dollar value). If ETH crashes to $2,000 tomorrow, your USDC is still worth $3,500. You can later swap back into ETH at a lower price, or deposit the USDC into Aave to earn 4% interest while you wait. The whole process took one transaction and 12 seconds.
What People Get Wrong
All stablecoins are equally safe
USDC (issued by Circle, US-regulated, monthly reserve attestations) carries very different risk than USDT (Tether, historically opaque about reserves, offshore) or algorithmic stablecoins (most have failed). "Stablecoin" is a category, not a safety guarantee.
Stablecoins cannot lose their peg
They can and do. USDC briefly traded at $0.87 in March 2023 when Silicon Valley Bank (holding $3.3B of Circle reserves) collapsed. UST collapsed to near-zero in May 2022. Pegs are maintained by mechanisms that can fail under extreme stress.
Stablecoins are the same as having dollars in a bank
You hold a token issued by a company. If that company becomes insolvent, the token may not be redeemable. There is no FDIC insurance on stablecoin holdings. You are trusting the issuer to actually hold the reserves they claim.
You do not need to worry about which stablecoin you use
Different stablecoins have different risk profiles, different DeFi integrations, and different liquidity levels. USDC is preferred for regulated interactions. DAI for decentralization. USDT has the deepest trading liquidity but more counterparty questions. Your choice should match your priorities.
Keep Reading
Sources & Further Reading
- DefiLlama Stablecoins
Track market caps, peg stability, and chain distribution of all stablecoins
Questions People Also Ask
- Are stablecoins regulated?
- Increasingly yes. The US, EU (MiCA), and other jurisdictions are implementing stablecoin-specific regulations covering reserve requirements, disclosure, and issuer licensing. USDC and USDT issuers are subject to varying degrees of regulatory oversight depending on jurisdiction.
- Do stablecoins earn interest?
- The tokens themselves do not earn interest (unlike a savings account). But you can deposit stablecoins into lending protocols (Aave, Compound) or staking programs to earn 3-8% yield. The yield comes from borrowers paying interest on their loans, not from the stablecoin issuer.
- Why are there so many different stablecoins?
- Different issuers, different reserve structures, different blockchain deployments, and different regulatory statuses. Some exist for specific ecosystems (FRAX for DeFi composability, PYUSD for PayPal users). Competition drives innovation in how pegs are maintained and reserves are managed.