Look at a list of crypto prices and you will often see pairs like BTC/USDT, ETH/USDT or SOL/USDT. That "USDT" is not a typo for USD. It is a stablecoin — a cryptocurrency designed to hold a steady value of one US dollar. Stablecoins have become the plumbing of crypto markets: the unit most prices are quoted in, the asset traders move into when they want to step out of volatility, and the bridge between traditional money and blockchain networks.
This guide explains what stablecoins are, the different ways they try to stay stable, how USDT works, what can make a stablecoin lose its peg, and what all of this means when you read or trade a crypto price quoted against USDT.
What is a stablecoin?
A stablecoin is a crypto token that aims to keep a stable value relative to a reference asset — most commonly one US dollar. Unlike Bitcoin or Ethereum, whose prices float freely, a stablecoin is engineered to trade at, or very near, its target price.
Stablecoins exist because crypto traders and users wanted something that:
- moves on blockchain networks as quickly and as easily as other crypto assets,
- is available around the clock, and
- does not swing in value like other cryptocurrencies.
Holding a stablecoin lets a trader step out of a volatile position without converting back to a bank currency, which can be slower and involve more intermediaries.
How stablecoins try to stay stable
There are three main designs.
1. Fiat-backed (reserve-backed) stablecoins
The issuer holds reserves — cash, short-term government securities and similar assets — intended to cover every coin in circulation. Approved customers can generally create new coins by depositing dollars, and redeem coins for dollars. If the coin trades below $1 elsewhere, traders can buy it cheaply and redeem it for $1; if it trades above $1, they can create new coins and sell them. That arbitrage is what keeps the price close to the peg.
Examples: USDT (Tether) and USDC. Key dependency: the reserves really existing, being high-quality and being accessible when redemptions surge.
2. Crypto-collateralised stablecoins
These are backed by other cryptocurrencies locked in smart contracts, usually at more than 100% of the coins' value to absorb price swings in the collateral. If collateral value falls too far, positions are liquidated automatically to protect the peg.
Example: DAI, created through the MakerDAO system. Key dependency: the collateral's value and the smart contracts working correctly, especially during sharp market falls.
3. Algorithmic stablecoins
These attempt to maintain the peg mainly through supply rules and incentives, rather than full reserves. In May 2022 the largest algorithmic stablecoin, TerraUSD (UST), lost its peg and collapsed to a small fraction of a dollar, along with its sister token, wiping out tens of billions of dollars in market value. The episode showed how fragile designs without solid reserves can be under stress.
| Design | Backed by | Main strength | Main weakness |
|---|---|---|---|
| Fiat-backed | Cash and similar reserves held by an issuer | Simple redemption mechanism | Depends on the issuer and its reserves |
| Crypto-collateralised | Over-collateralised crypto in smart contracts | Transparent on-chain | Collateral can crash; contract risk |
| Algorithmic | Supply rules and incentives | No reserves needed | Has failed badly under stress |
How USDT works
USDT is issued by Tether, launched in 2014, and is the largest stablecoin by circulation. It is issued on several blockchains, including Ethereum and Tron.
Tether states that each USDT is backed by reserves and publishes reports on the composition of those reserves on its transparency page. Those reserves have included cash and cash equivalents, short-term government securities and other assets. The reports are attestations rather than full audits, and the adequacy and composition of Tether's reserves have been the subject of debate and of regulatory scrutiny over the years. For most users, the practical point is this: USDT's stability depends on confidence in the issuer and on the arbitrage mechanism working.
Why crypto is quoted in USDT
Most crypto trading happens between crypto assets rather than against bank currencies. USDT became a common quote currency because:
- it is close to a dollar, so prices are easy to understand,
- it moves on the same networks as other crypto assets, and
- many trading venues list far more pairs against USDT than against actual dollars.
So BTC/USDT means "the price of one bitcoin, measured in USDT". In normal conditions it is almost identical to BTC/USD.
When stablecoins lose their peg
A "de-peg" is when a stablecoin trades meaningfully away from its target. Causes include:
- Doubts about reserves. If holders fear the reserves are insufficient or inaccessible, they rush to redeem or sell, pushing the price down.
- Banking or custody problems. In March 2023 USDC fell well below $1 for a short period after its issuer disclosed that part of its reserves were held at Silicon Valley Bank, which had just failed. It recovered once access to those funds was assured.
- Design failure. Algorithmic designs like TerraUSD can enter a spiral when confidence breaks.
- Market stress. Even sound stablecoins can trade slightly off-peg during extreme volatility, when demand for them spikes or collapses.
What a de-peg means for a USDT-quoted price
If USDT trades at, say, $0.98, then BTC/USDT will appear about 2% higher than BTC/USD, because each USDT is worth less. Charts quoted in USDT can therefore move slightly for reasons that have nothing to do with Bitcoin itself. In normal conditions this effect is tiny, but it is worth understanding.
Stablecoins compared with money in a bank
| Dollar-pegged stablecoin | Dollars in a bank account | |
|---|---|---|
| Who stands behind it | The issuing company and its reserves | The bank, within a regulated banking system |
| Deposit insurance | Generally none | Often covered by a deposit-insurance scheme, up to a limit |
| Availability | Around the clock, on blockchain networks | Depends on banking hours and payment systems |
| Speed of transfer | Minutes, depending on the network | From seconds to days, depending on the system |
| Reversibility | Usually irreversible once sent | Some payments can be disputed or recalled |
| Main risk | Issuer, reserves, de-peg, custody | Bank failure beyond insured limits, inflation |
Neither is simply "better". Stablecoins are faster and always available within crypto markets; bank money sits inside a system of regulation and insurance that stablecoins generally do not have.
How to judge a stablecoin's health
You don't need to be an analyst to keep an eye on the basics:
- Its market price. Is it trading within a fraction of a cent of $1 across major venues? A persistent discount is a warning sign.
- Reserve disclosures. Does the issuer publish regular reports on what backs the coin, and are they recent? What share of reserves is cash or very short-term government debt?
- Redemption terms. Who can redeem coins for dollars, and with what minimums and fees? Arbitrage only holds the peg if redemption actually works.
- Concentration of use. How dependent is your own trading on a single stablecoin? If every pair you trade is quoted in it, a disturbance affects all of them at once.
- Regulatory news. Actions against an issuer, or new rules on who may hold or offer a coin, can change its risk quickly.
Stablecoin risks to keep in mind
The U.S. Commodity Futures Trading Commission warns that virtual currencies carry risks including volatility, platform failure and cyber-theft, and those warnings apply to stablecoins too:
- Issuer risk: you rely on the issuer to honour redemptions.
- Reserve risk: reserves may be weaker or less liquid than they appear.
- Regulatory risk: rules can change, affecting issuers or where coins can be used.
- Custody risk: coins held on a platform depend on that platform's security and solvency.
- Scam risk: fraudsters frequently ask victims to pay in stablecoins. The U.S. Federal Trade Commission notes that only scammers demand payment in cryptocurrency. Our article on crypto trading scams and risks covers the common patterns.
Common misunderstandings
- "Stablecoins can't lose value." They are designed to hold their peg, and usually do, but several have broken it — some briefly, one permanently.
- "USDT and USD are the same thing." USDT is a token issued by a private company, intended to be worth one dollar. A bank dollar is a claim within the regulated banking system.
- "Holding stablecoins earns nothing, so it's pointless." Their purpose in trading is stability and convenience, not yield. Offers of unusually high interest on stablecoins deserve particular scrutiny.
- "All stablecoins are alike." Reserve-backed, crypto-collateralised and algorithmic designs fail in different ways and carry different risks.
Stablecoins and trading strategy
For traders, stablecoins have a few practical roles:
- The base for measuring results. Profits and losses on crypto pairs quoted in USDT are measured in a dollar-like unit, which makes them easier to compare.
- A temporary refuge. Moving out of volatile positions into a stablecoin reduces exposure to crypto price swings — though not to stablecoin-specific risks.
- A reminder of correlation. Because so many pairs share the same quote currency, a USDT disturbance affects many charts at once.
- A measure of market mood. Large flows into stablecoins can reflect traders stepping out of volatile positions; flows back out can accompany renewed buying. Treat this as background context rather than a signal.
A worked example
A trader buys 0.05 BTC on a BTC/USDT chart at 60,000 USDT, risking a move down to 58,500 USDT (a 1,500 USDT stop distance, 75 USDT at risk). The trade reaches 62,000 USDT and the trader exits for a 100 USDT gain.
In normal conditions, those 100 USDT are worth about $100. If USDT were trading at $0.995 at the time, the gain would be worth about $99.50. The difference is small, but it illustrates the point: a USDT-quoted result is a result measured in USDT.
Stablecoin pairs on RumiEX
On RumiEX, crypto instruments such as Bitcoin, Ethereum and Solana are listed against USDT and marked OTC, which means their prices are quoted by RumiEX's own pricing engine rather than taken from an external exchange. You can see the current list and live prices on the markets page, and our Bitcoin vs Ethereum guide explains the two largest assets in more detail.
Key takeaways
- Stablecoins are crypto tokens designed to hold a steady value, usually one US dollar.
- They are fiat-backed, crypto-collateralised or algorithmic; algorithmic designs have failed badly under stress.
- USDT is the largest stablecoin; its stability depends on its issuer's reserves and on redemption arbitrage.
- Stablecoins can lose their peg, as USDC briefly did in March 2023 and TerraUSD did permanently in 2022.
- A price quoted in USDT is measured in USDT — usually almost the same as dollars, but not guaranteed to be.
Next: learn how to protect yourself in crypto trading scams and risks.
Frequently asked questions
What is a stablecoin?
A stablecoin is a cryptocurrency designed to keep a stable value, usually one US dollar per coin. It aims to combine the stability of a traditional currency with the ability to move on blockchain networks like other crypto assets.
What does BTC/USDT mean?
It is the price of one bitcoin expressed in USDT, a dollar-pegged stablecoin. Because USDT is designed to be worth one dollar, BTC/USDT is usually very close to Bitcoin's price in US dollars, but the two can differ slightly if USDT trades away from exactly one dollar.
Is USDT backed by real dollars?
Tether, the company that issues USDT, states that USDT is backed by reserves and publishes periodic reports on those reserves on its transparency page. The reserves include a range of assets, not only cash. How much assurance those reports provide has been debated, and holders rely on the issuer for redemption.
Can a stablecoin lose its peg?
Yes. Stablecoins have traded below one dollar during periods of stress. In March 2023 USDC briefly fell well below its peg when some of its reserves were held at a failed US bank, and in May 2022 the algorithmic stablecoin TerraUSD collapsed almost entirely.
Are stablecoins risk-free?
No. Their main risks are the quality and accessibility of reserves, the issuer's ability to meet redemptions, regulatory action, and technical or custody risks. They are designed to be stable, not guaranteed to be.
Sources and further reading
Written and reviewed by the RumiEX Editorial Team. This article is for education only and is not financial, investment or tax advice. Read our editorial standards.