Explore the different types of stablecoins including fiat-backed (USDC, USDT), crypto-backed (DAI), and algorithmic models. Learn how each maintains its peg and their role in DeFi lending.
Cryptocurrencies like Bitcoin and Ethereum are known for their price volatility. While this volatility creates opportunities for traders and long-term investors, it makes everyday transactions and financial planning difficult. If you receive your salary in Bitcoin, its purchasing power could swing 10% by the time you pay rent.
Stablecoins solve this problem by creating cryptocurrencies designed to maintain a stable value, usually pegged to a traditional currency like the US dollar. They combine the programmability, speed, and borderless nature of crypto with the price stability of traditional money.
Stablecoins have become one of the most important building blocks of the crypto ecosystem. They facilitate trillions of dollars in annual transaction volume, serve as the primary trading pair on exchanges, and are the assets most commonly borrowed through DeFi lending protocols. Understanding the different types of stablecoins, how they maintain their peg, and their respective risk profiles is essential knowledge for anyone participating in crypto lending or DeFi.
Not all stablecoins are created equal. They differ fundamentally in how they maintain their dollar peg, and these differences have major implications for their reliability, risk profile, and use cases.
Fiat-backed stablecoins are the simplest and most widely used type. For every stablecoin in circulation, the issuing company holds an equivalent amount of reserves in traditional financial instruments, typically cash, Treasury bills, and other short-term, highly liquid assets.
When you buy a fiat-backed stablecoin, the issuer takes your dollars and mints new tokens. When you redeem them, the issuer burns the tokens and returns dollars. This straightforward backing mechanism makes fiat-backed stablecoins relatively easy to understand and generally reliable at maintaining their peg.
USDC is issued by Circle, a regulated financial technology company. It has become one of the most trusted stablecoins in the ecosystem, particularly among institutional users and DeFi protocols.
Key characteristics of USDC:
USDC briefly lost its peg in March 2023 when Silicon Valley Bank (which held $3.3 billion of Circle's reserves) collapsed. The peg recovered within days after the FDIC guaranteed all deposits, but the episode highlighted that even well-managed fiat-backed stablecoins carry some risk from their banking relationships.
USDT, also known as Tether, is the oldest and largest stablecoin by market capitalization. Despite ongoing controversy about its reserves, it remains the most widely traded stablecoin globally and dominates trading volume on both centralized and decentralized exchanges.
Key characteristics of USDT:
Tether has faced scrutiny over the composition and adequacy of its reserves. While the company has published attestation reports showing reserves exceeding liabilities, critics note that these are not full audits and that the reserve composition has historically included commercial paper and other less liquid assets.
Despite these concerns, USDT has maintained its peg through multiple market crises and remains deeply embedded in the crypto trading infrastructure.
Several other fiat-backed stablecoins serve specific niches:
Crypto-backed stablecoins take a fundamentally different approach. Instead of trusting a company to hold dollar reserves, they use cryptocurrency locked in smart contracts as collateral. This makes them more decentralized and transparent but introduces different risks.
DAI is the most prominent crypto-backed stablecoin, created and managed by MakerDAO (now rebranded as Sky). It has been a cornerstone of DeFi since its launch in 2017 and demonstrates that a stable dollar-pegged asset can exist without centralized backing.
How DAI Works:
DAI is created through a process called "minting." Users deposit collateral (ETH, wBTC, USDC, and other approved assets) into Maker Vaults, and in return, they can mint DAI up to a certain percentage of their collateral value.
Because crypto is volatile, DAI positions must be over-collateralized. If you want to mint 1,000 DAI, you might need to deposit $1,500 worth of ETH (a 150% collateralization ratio). If the value of your ETH drops and your collateral ratio falls below the minimum threshold, your position is automatically liquidated to protect the system.
Peg Maintenance Mechanisms:
DAI maintains its dollar peg through several mechanisms:
Evolution and Controversy:
DAI has evolved significantly over the years. It originally accepted only ETH as collateral (Single-Collateral DAI) before expanding to multiple collateral types (Multi-Collateral DAI). Notably, a significant portion of DAI's backing now comes from USDC and real-world assets, which some argue compromises its decentralization.
Algorithmic stablecoins attempt to maintain their peg through automated mechanisms that expand and contract the supply based on demand, without requiring direct collateral backing. This category has proven to be the most experimental and risky.
How Algorithmic Models Work:
The basic concept is that when the stablecoin trades above $1, the protocol mints new tokens to increase supply and push the price down. When it trades below $1, the protocol reduces supply (through burning, bonding, or other mechanisms) to push the price up.
Some algorithmic designs use a dual-token system where a secondary "seigniorage" token absorbs the volatility. Others use partial collateralization combined with algorithmic mechanisms.
The Terra/UST Collapse:
The most infamous algorithmic stablecoin was TerraUSD (UST), which used a dual-token system with LUNA. When UST demand fell sharply in May 2022, the algorithmic mechanism entered a death spiral: UST lost its peg, causing LUNA to be minted in massive quantities, which crashed LUNA's price, which further undermined confidence in UST, creating a feedback loop that destroyed over $40 billion in value within days.
The Terra collapse is one of the most significant events in crypto history and led to widespread skepticism about purely algorithmic stablecoin designs.
Current State:
After the Terra collapse, purely algorithmic stablecoins have largely fallen out of favor. Most newer designs incorporate some element of collateral backing alongside algorithmic mechanisms, creating hybrid approaches. Notable examples include:
Stablecoins are the lifeblood of DeFi lending. Understanding this relationship helps you make informed decisions about which stablecoins to borrow and why.
When you deposit Bitcoin as collateral on a lending protocol and borrow against it, you are almost always borrowing stablecoins. This makes sense because borrowers typically want a stable-value asset they can spend, convert to fiat, or use in other DeFi activities without worrying about price volatility.
The choice of which stablecoin to borrow matters:
Different stablecoins often have different borrowing rates on the same lending protocol. These differences arise from supply and demand dynamics within each stablecoin's lending pool. If a particular stablecoin has high deposit supply but low borrowing demand, its rates will be lower.
This is where aggregation becomes valuable. Platforms like Borrow by Sats Terminal compare rates across multiple stablecoins and protocols simultaneously, helping you find the cheapest borrowing option for your needs.
Some lending protocols also accept stablecoins as collateral. Because stablecoins have minimal price volatility, they can be used with very high loan-to-value ratios. This is useful for strategies like leveraged stablecoin yield farming, though it is outside the scope of Bitcoin-backed borrowing.
Not all dollar-pegged assets carry the same risk. Here is a framework for assessing stablecoin safety.
For fiat-backed stablecoins, the quality and transparency of reserves is paramount. Questions to ask include:
For crypto-backed and algorithmic stablecoins, smart contract security is critical:
How well has the stablecoin maintained its peg during market stress? Minor deviations (0.1-0.5%) during extreme volatility are normal. Larger de-pegging events (several percent or more) are warning signs.
Larger stablecoins with deeper liquidity are generally safer because they can absorb larger redemptions without stress. Smaller stablecoins may struggle during periods of high redemption demand.
The regulatory environment for stablecoins is evolving. Stablecoins from issuers with strong regulatory relationships (like USDC) may be better positioned for long-term viability as regulations develop.
For Bitcoin holders using platforms like Borrow by Sats Terminal, stablecoins play a specific and important role.
The primary use case for borrowing stablecoins against Bitcoin is accessing dollar-denominated liquidity without selling your BTC. Whether you need funds for expenses, want to invest in another opportunity, or are managing taxes, borrowing stablecoins lets you unlock value from your Bitcoin holdings while maintaining your long-term position.
When borrowing through Borrow, consider these factors:
Because Borrow is fully non-custodial, the stablecoins you borrow go directly to your self-custodial Privy wallet. You maintain full control over these borrowed assets and can use them however you choose. No intermediary holds your borrowed stablecoins or restricts how you use them.
The stablecoin landscape continues to evolve rapidly, driven by regulatory developments, technological improvements, and market dynamics.
Governments worldwide are developing stablecoin-specific regulations. The US, EU (through MiCA), and other jurisdictions are establishing requirements around reserves, redemption rights, and issuer licensing. These frameworks will likely consolidate the market around compliant issuers.
A growing trend is stablecoins that automatically generate yield for holders by investing reserves in Treasury bills or other income-generating assets. This blurs the line between stablecoins and money market funds.
Some view CBDCs as potential competitors to private stablecoins. However, CBDCs and stablecoins serve different purposes, and the DeFi ecosystem will likely continue to rely on private stablecoins due to their programmability and permissionless nature.
Stablecoins are essential infrastructure in the crypto ecosystem, providing price stability while preserving the benefits of blockchain technology. The three main types (fiat-backed, crypto-backed, and algorithmic) each have distinct mechanisms, risk profiles, and trade-offs.
For Bitcoin holders using DeFi lending, understanding stablecoin types helps you make informed decisions about which assets to borrow. Fiat-backed stablecoins like USDC and USDT offer reliability and liquidity. Crypto-backed options like DAI offer decentralization and transparency. Algorithmic designs have largely been discredited by the Terra collapse and carry the highest risk.
Platforms like Borrow by Sats Terminal simplify stablecoin borrowing by aggregating rates across protocols and stablecoins, helping you find the best terms for your Bitcoin-backed loan. With a self-custodial wallet and no KYC requirements, Borrow provides a secure, private way to access stablecoin liquidity against your Bitcoin holdings.
Related Guides
Basics
Learn what stablecoins are, how they maintain their peg, and why they matter. This beginner's guide covers USDC, USDT, DAI, and how stablecoins are used in crypto lending and borrowing.
Basics
Discover how cryptocurrency lending works, the roles of lenders and borrowers, and why it has become a cornerstone of decentralized finance. Learn about interest rates, collateral, and how platforms like Borrow by Sats Terminal simplify the process.
Common Questions
There are three main types: fiat-backed stablecoins (like USDC and USDT) backed by cash and cash equivalents held in bank accounts, crypto-backed stablecoins (like DAI) backed by cryptocurrency collateral locked in smart contracts, and algorithmic stablecoins that use automated mechanisms to maintain their peg without direct collateral backing.
