What Are Stablecoins and How Do They Keep Their Peg?

What a stablecoin actually is

A stablecoin is a cryptocurrency designed to hold a steady value instead of fluctuating with the market. Almost all of them are pegged 1:1 to the US dollar, so one unit is meant to always be worth about one dollar, whether the broader crypto market is up 20% or down 20% that week.

That's the whole point. Bitcoin and most other tokens are volatile by design: their price is set by supply and demand and can swing hard in a single day. A stablecoin tries to combine crypto's biggest advantage, being able to send value anywhere in the world quickly on a blockchain, with the price stability of regular money. You get the transferability of crypto without the rollercoaster.

Why they're useful

Stablecoins solve a practical problem for anyone active in crypto. If you sell a position and want to sit in cash without actually leaving the blockchain and going through a bank, you move into a stablecoin instead. It's a parking spot between trades that doesn't require an off-ramp to your bank account every time you want out of a volatile asset.

They've also become the base layer for most trading and DeFi (decentralized finance, covered in our DeFi guide) activity. Most spot and perpetual futures pairs are quoted against a stablecoin rather than the dollar directly, and most lending, borrowing, and yield products in DeFi are built around them. On top of that, stablecoins give people a way to hold and move dollar-equivalent value on-chain without needing a traditional bank account at all, which matters a lot in places where banking access is unreliable or restricted.

The main ways a stablecoin holds its peg

Not every stablecoin works the same way under the hood. There are three broad designs, and the differences between them matter a lot when you're deciding whether to trust one.

Fiat-collateralized. This is the simplest and most common model. A company holds real dollar reserves (cash, short-term government debt, and similar low-risk assets) in a bank or custodian account, and issues one token on-chain for every dollar it holds. In theory, and ideally in practice, you can redeem a token for a real dollar at any time. The peg holds because the backing is straightforward: one token, one dollar sitting somewhere.

Crypto-collateralized. Instead of dollars in a bank, these stablecoins are backed by other cryptocurrencies, like Ether, locked up in a smart contract. Because crypto itself is volatile, these systems typically require over-collateralization, meaning you might need to lock up $150 worth of crypto to mint $100 worth of the stablecoin. That cushion protects the peg if the collateral's price drops. This model is more decentralized, since no single company custodies the reserves, but it's also more complex and carries its own risks if collateral prices fall sharply and fast.

Algorithmic. These stablecoins don't rely on full collateral backing at all. Instead, they use code and market incentives, like minting and burning a paired token, to push the price back toward $1 when it drifts. It's an elegant idea on paper, but it depends entirely on people continuing to trust and use the system. Algorithmic designs have historically been the riskiest category, and this space has seen high-profile failures when confidence broke and the peg couldn't hold. Worth knowing before you treat any algorithmic stablecoin as equivalent to cash.

What "depegging" means

Depegging is when a stablecoin's market price drifts away from its intended $1 value, trading at $0.97 or $1.05 instead of holding steady. A small, brief wobble can happen during periods of heavy trading and usually corrects itself quickly. A larger or sustained depeg is a warning sign, usually pointing to a problem with the reserves backing the coin, a liquidity crunch making it hard to redeem at par, or a broader loss of confidence in the issuer or the mechanism holding the peg together.

The severity matters. A stablecoin that dips to $0.995 for an hour during volatile markets is a different situation than one that falls to $0.60 and stays there. When you're holding a stablecoin as a safe parking spot, it's worth knowing that "stable" is a design goal, not a guarantee.

Regulation is catching up

Stablecoin regulation has become a major, active topic for governments and financial regulators around the world, and that's only accelerated as stablecoins have grown into a genuine tool for payments and remittances, not just crypto trading. The general direction is toward requiring issuers to prove what's actually backing their tokens: how much is held, in what form, and how regularly it's verified and disclosed.

Exactly what rules apply, and how strict they are, still varies a lot by country and continues to change. If you're using stablecoins for anything beyond short-term trading, it's worth staying aware that the regulatory landscape around them is still being written, and that can affect which stablecoins remain available, how they're taxed, and what protections you actually have.

Not all stablecoins are equally trustworthy

"Stablecoin" describes a goal, not a guarantee. A fiat-collateralized coin backed by verifiable dollar reserves, a crypto-collateralized coin backed by over-collateralized crypto, and an algorithmic coin backed mostly by market confidence are three very different risk profiles wearing the same label. Before you treat any stablecoin as interchangeable with cash, it's worth spending a few minutes understanding how it's actually backed, who issues it, and how that backing gets verified. Once you're comfortable with that, terms like the ones in our crypto glossary will make the rest of the trading and DeFi world easier to navigate.