If you have swapped tokens on Base, there is a good chance one side of that swap was a stablecoin. Stablecoins are the quiet workhorses of crypto: assets designed to hold a steady value, usually one US dollar, so you can move funds, price goods, or park value without riding the volatility of ETH or other tokens.
But "stable" is a design goal, not a guarantee. Different stablecoins use very different mechanisms to hold their peg, and those mechanisms come with different risks. Understanding them helps you make more informed decisions about which stablecoins you hold and how much you trust that peg.
What a stablecoin actually is
A stablecoin is a token, usually an ERC-20 token on a network like Base, whose issuer or protocol tries to keep its market price close to a reference value, most commonly $1. Unlike a bank deposit, a stablecoin lives on a blockchain, moves with a normal wallet transaction, and can be used in DeFi protocols the same way any other token can.
The "peg" is simply that target price. When people say a stablecoin "depegged," they mean its market price moved noticeably away from that target, even if only temporarily.
There are three broad approaches to keeping a token pegged: fiat-backed reserves, crypto-collateralized reserves, and algorithmic mechanisms.
Fiat-backed stablecoins: USDC and similar tokens
The most widely used stablecoins today, including USDC, are backed by real-world reserves held off-chain. For every token in circulation, the issuer holds an equivalent amount of cash and short-term government debt, such as US Treasury bills, at regulated financial institutions.
The peg holds because the token is redeemable, at least for large approved partners, for the actual dollars behind it. Circle, the issuer of USDC, publishes monthly attestation reports from an independent accounting firm showing that reserves are held almost entirely in cash and Treasury bills. In the US, the GENIUS Act, signed into law in 2025, now requires payment stablecoin issuers to hold fully liquid reserves and publish regular public attestations.
This model's strength is simplicity: the token is meant to be a direct digital representation of a dollar sitting in reserve. Its main risks are counterparty and regulatory ones. You are trusting that the issuer actually holds the reserves it claims, that those reserves stay liquid, and that redemption keeps working during stress. A stablecoin's on-chain code cannot verify what is happening in a bank account, which is exactly why independent attestations matter.
Crypto-collateralized stablecoins: DAI
DAI, governed by the MakerDAO protocol (now part of the Sky ecosystem), takes a different approach. Instead of holding dollars in a bank, users lock up crypto assets, such as ETH or other approved collateral, in a smart contract and mint DAI against that collateral.
The key detail is over-collateralization. To mint a given amount of DAI, users must deposit collateral worth significantly more, often 150% or higher depending on the asset. If the collateral's value falls and the position becomes undercollateralized, automated smart contracts can liquidate it, selling the underlying assets to keep the system solvent and DAI close to its peg.
This model does not depend on trusting a single company's bank reserves. Everything is verifiable on-chain. But it introduces different risks: the collateral itself is volatile, liquidations can happen quickly in a market crash, and the protocol's governance and smart contracts become part of what you are trusting.
Algorithmic stablecoins: a cautionary category
A third approach tries to hold the peg purely through algorithmic supply and demand mechanisms, minting or burning tokens based on market price, without full backing by outside collateral. These designs are attractive in theory because they do not require holding reserves at all.
In practice, pure algorithmic stablecoins have a poor track record. The best-known example, TerraUSD (UST), collapsed in May 2022 when its price fell far below $1 and the mechanism meant to restore the peg instead accelerated the decline, wiping out tens of billions of dollars in value within days. Since then, most serious projects have moved toward hybrid models that keep at least partial real collateral behind the token, and pure algorithmic designs are generally treated with much more caution across the industry.
Why a peg can still slip, even for well-backed tokens
Even reputable, well-collateralized stablecoins can trade slightly off their peg for short periods. A few common reasons:
- Market stress or panic. If many holders try to redeem or sell at once, exchange prices can move away from $1 even if the underlying reserves are fully intact, simply due to supply and demand on that particular venue.
- Liquidity pool imbalances. On a decentralized exchange, a stablecoin's price in a given pool is set by the ratio of assets in that pool. A large trade can temporarily push the price a fraction of a cent away from $1 until arbitrage traders bring it back in line.
- Issuer or banking news. Any real or rumored problem with an issuer's reserves or banking partners can cause a temporary dip, even before the facts are confirmed.
- Smart contract or bridge issues. A wrapped or bridged version of a stablecoin depends on the bridge working correctly. Problems with the bridge, not the underlying asset, can cause the wrapped version to trade below its target.
Small, brief deviations of a fraction of a cent are normal and usually correct themselves quickly through arbitrage. Sustained, large deviations are the signal worth paying attention to.
What this means when you are swapping on Base
When you swap into or out of a stablecoin, you are relying on whichever peg mechanism backs that specific token. A few practical habits:
- Know what backs the stablecoin you are holding. Fiat-backed, crypto-collateralized, and algorithmic tokens carry different risk profiles, even if they all show "$1.00" in your wallet.
- Check that you are interacting with the genuine contract, not a look-alike token with a similar name. Scam tokens sometimes mimic well-known stablecoin names.
- Watch for unusually large price impact when swapping a stablecoin pair. A well-arbitraged pool should show a swap price very close to $1, particularly for smaller trade sizes.
- Remember that a stablecoin is not risk-free. It removes exposure to crypto price volatility, but it does not remove reserve, smart contract, or bridge risk entirely.
Stablecoins are one of the most useful tools in crypto precisely because they let you hold value without betting on price direction. Understanding how each one actually maintains its peg is the difference between trusting a label and trusting the mechanism behind it.
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