Stablecoin
A stablecoin is a type of cryptocurrency designed to maintain a stable value, typically pegged to a fiat currency such as the U.S. dollar, by holding reserves or through algorithmic mechanisms to prevent the extreme price volatility characteristic of other cryptocurrencies.
Stablecoins emerged as a solution to one of the most significant practical limitations of cryptocurrencies like Bitcoin and Ethereum: their extreme price volatility makes them poorly suited as a medium of exchange or unit of account for everyday transactions. A merchant or borrower cannot easily price goods or repay a loan in an asset that might lose 20% of its value overnight. Stablecoins attempt to combine the programmability and borderless transfer capabilities of cryptocurrencies with the price stability of fiat currencies.
The largest stablecoins by market capitalization as of 2024 are Tether (USDT) and USD Coin (USDC), both pegged to the U.S. dollar at a 1:1 ratio. Fiat-backed stablecoins claim to hold reserves of actual U.S. dollars (or dollar-equivalent assets such as short-term Treasuries) sufficient to redeem every outstanding token. The quality and transparency of these reserves is a critical consideration: Tether has faced persistent scrutiny about the composition and auditing of its reserves, while USDC, issued by Circle, has positioned itself as more transparent and compliant.
Algorithmic stablecoins attempt to maintain their peg through supply-and-demand mechanisms rather than holding reserves. The catastrophic collapse of TerraUSD (UST) and its sister token Luna in May 2022 — which destroyed approximately $40 billion in market value within days — provided a stark demonstration of the failure modes inherent in algorithmic stablecoin designs that lack genuine collateral backing. The Terra collapse triggered widespread contagion across crypto markets and accelerated regulatory scrutiny of the stablecoin sector.
A third category is collateralized stablecoins, where the peg is maintained by over-collateralization with other crypto assets. DAI, issued by MakerDAO, is the most prominent example: users lock up Ethereum or other approved collateral worth more than 150% of the DAI minted, providing a buffer against collateral price declines. If collateral value falls below a threshold, automatic liquidations reduce the outstanding supply of DAI.
From a U.S. regulatory perspective, stablecoins have attracted intense attention. The President's Working Group on Financial Markets published a report in 2021 recommending that stablecoin issuers be regulated as insured depository institutions (banks). Congress has debated stablecoin legislation that would impose reserve, audit, and registration requirements on issuers. The Federal Reserve has also expressed concerns about the potential for large stablecoins to create systemic risks to the financial system if their reserves were to face a 'run.' Investors using stablecoins for yield farming, trading, or remittances should be aware that the regulatory landscape is still developing and that even ostensibly stable assets can experience de-pegging events under stress.