Total stablecoin supply, mid-2026
~$290B
Bigger than most banks. Two coins hold ~88% of it.
Stablecoins and moving money.
A stablecoin is a token that promises to be worth one dollar. That's the easy part. The whole lesson is who's on the other side of that promise, what they're holding to keep it, and what happens on the weekend they can't. Not advice. Just the map.
not advice · US view · rules still being written
Why this lesson exists
You will touch a stablecoin the second you go on-chain. It's the dollar you park in between trades, the thing you send home, the unit every DEX prices against. Most people treat all of them as "a dollar" and never ask the two questions that matter: what is backing this token, and can I actually get my dollar back when everyone asks at once? Three times now the answer was no. Those three times are most of this page.
Three kinds. Only one of them has really held.
Every stablecoin answers the same question — "why is this worth a dollar?" — in one of three ways. The difference is not branding. It's what happens under stress.
Fiat-backed
a dollar in a bank per token
A company holds real dollars and short government debt, and issues one token per dollar. You trust the company and its bank. This is the boring one that mostly works.
USDC · USDT · ~88% of the market
Crypto-backed
over a dollar of crypto locked up
You lock more than a dollar of volatile crypto in a contract to mint one stable dollar. Overcollateralized on purpose. No company holding cash, but you're one crash away from liquidation.
DAI · USDS · on-chain, code-run
Algorithmic
backed by faith and a sister token
No real assets. The peg is held by a trade you can always do with a second token the project prints. When faith goes, the math runs backward. This is the graveyard.
UST (dead) · see section 05
| Type | What's behind $1 | Fails when | Examples |
|---|---|---|---|
| Fiat-backed | Cash + short US Treasuries held by a company | Its bank fails, or it lied about reserves | USDC, USDT |
| Crypto-backed | More than $1 of crypto locked in a contract | Collateral crashes faster than it can liquidate | DAI, USDS |
| Algorithmic | Nothing real — a mint/burn trade with a second token | Confidence drops. Then it's gone. | UST (dead) |
Takeaway: "stablecoin" is not one thing. A fiat-backed token can survive a scare and repeg. An algorithmic one that loses the peg hard usually doesn't come back. Know which kind you're holding before you park real money in it.
What actually backs the fiat-backed ones.
The two that matter are USDC (Circle) and USDT (Tether). Together they're roughly 88% of the whole market. Both claim to be a dollar. Here's what that claim rests on, from the actual disclosures.
USDC. As of year-end 2025, Circle held about 88% of USDC reserves in the Circle Reserve Fund — a government money-market fund managed by BlackRock, holding short-dated US Treasuries (weighted-average maturity under 60 days) plus overnight repos backed by Treasuries. The custodian is BNY. The rest sits as cash at big global banks. Circle publishes holdings down to a daily view on the fund and went public in 2025, so its numbers now live inside SEC filings.
USDT. Tether's reserves are now dominated by US Treasuries too, and it publishes quarterly attestations from BDO. That's the good news. The complicated news is the history, and the fact that an attestation is not the same thing as an audit. That gap is the next two sections.
Attestation is not audit — learn the difference
An attestation is an accountant confirming that on one day, the reserves added up. An audit is a deeper, ongoing examination of the whole operation. Every major stablecoin publishes attestations. None of the big ones has historically published a full financial audit of the issuer. It's a real distinction, and it's exactly where trust gets tested.
the lessonWhat counts as a "good" reserve, and why maturity matters
Not all "backing" is equal. A reserve is only as safe as how fast it converts to cash without a loss when everyone redeems at once.
- Cash at a bank — instant, but it's a deposit, and banks fail. That's the whole USDC/SVB story below.
- Short Treasury bills (days to weeks) — the gold standard. Deep market, backed by the US government, priced by the minute.
- Long bonds — pay more, but you eat a loss if you're forced to sell early into a rush. This is roughly what broke money-market funds in 2008.
- Commercial paper, loans, "other" — higher yield, murkier. Older Tether reserves leaned here. The market punished it until they moved to Treasuries.
The new US law leans hard on this: it forces reserves into cash, insured deposits, and Treasury bills maturing in 93 days or less. Short and boring, on purpose. More in section 09.
Takeaway: "fully backed" means nothing until you read what it's backed by. Short Treasuries and cash at a solid bank is the answer you want. Anything reaching for yield in the reserve is reaching for risk with your dollar.
The weekend USDC broke, hour by hour.
The best stablecoin in the business, the transparent regulated one, lost its peg in March 2023. Not because Circle lied. Because a bank holding part of its cash failed, and cash in a bank is a bank deposit like any other.
| When | What happened |
|---|---|
| Fri Mar 10 | Regulators seize Silicon Valley Bank. Circle holds cash there. |
| Fri night | Circle discloses $3.3B of its ~$40B reserves is stuck at SVB — about 8%. |
| Sat ~2am | USDC falls to ~$0.87. Traders can't tell if the $3.3B is gone. |
| Sat–Sun | Stays under a dollar all weekend. Panic and forced redemptions. |
| Sun 6:15pm | Treasury, Fed, and FDIC announce all SVB depositors made whole. |
| Mon Mar 13 | Circle reopens redemptions. USDC repegs to $1.00. |
The lesson traders actually took
USDC recovered because the backing was genuinely there — the $3.3B came back when SVB's depositors were covered. But for 48 hours nobody knew that, and holding "cash" turned out to mean holding a bank's promise. The safest fiat stablecoin in the world still carried the risk of the banking system it lived on top of. That is not a bug you can code away. It's the shape of the thing.
Terra: $45 billion, gone in a week.
USDC dipped and came back. UST — the biggest algorithmic stablecoin ever — dipped and kept going to zero. This is the case study for why "algorithmic" is a graveyard, not a category.
UST held its dollar with a trade, not a reserve. You could always burn $1 of UST for $1 of its sister token LUNA, and the reverse. When UST was worth $1, fine. But that loop only works if LUNA holds value. The peg was propped up by a lending protocol called Anchor paying ~19.5% on UST deposits — a yield with no real business behind it, pulling in billions of hot money.
- The tell was the yield. 19.5% on a "stable" dollar is not stable-anything. It was a subsidy paying people to hold the thing, and subsidies end.
- The tell was the reflexivity. The asset defending the peg (LUNA) was worth less exactly when the peg needed defending most. Backing that evaporates under stress is not backing.
- It didn't come back. Unlike USDC, there was no real reserve to reopen redemptions against. Once the spiral started, there was nothing underneath it.
Takeaway: if a stablecoin pays you a big yield just to hold it, ask where the yield comes from. If the answer is "a token the project prints," you're looking at UST with a new logo. Every algorithmic peg that has broken hard has stayed broken.
Tether's long shadow.
USDT is the most-used stablecoin on earth — around $184B, roughly 63% of the market as of mid-2026. It has also, historically, been the least transparent, and it has paid real fines for saying it was backed when it wasn't. Both things are true. Hold them at once.
| When | Who | The finding | Cost |
|---|---|---|---|
| Feb 2021 | NY Attorney General | Found USDT was not fully backed at times in 2017–2018; Bitfinex tapped Tether funds to cover an $850M hole. Barred from New York. | $18.5M |
| Oct 2021 | CFTC | "Fully backed" was untrue for substantial periods from June 2016 to Feb 2019; reserves included unsecured receivables and non-fiat assets. | $41M |
Where it stands now: Tether's reserves are Treasury-heavy, and it publishes quarterly BDO attestations. It has been enormously profitable off the interest on those Treasuries. But it has still never published a full audit of the issuer, and the whole reason regulators care about stablecoins traces partly back to this file.
How to hold this honestly
Plenty of people use USDT every day without a problem — it's the deepest liquidity in crypto, especially outside the US. That's real. It's also true that its history is the strongest argument in the room for the reserve rules and disclosure the new US law demands. Using it and respecting its track record are not in conflict. Size your trust to the transparency, not the market cap.
Moving money: where stablecoins actually earn their keep.
Forget trading for a second. The reason serious people care about stablecoins is boring and huge: sending dollars is still slow and expensive, and a stablecoin is dollars that move at internet speed. The global remittance market is around $900B a year, and the fees on it are a quiet tax on the people who can least afford it.
Cost of sending ~$200 home. Legacy average from the World Bank; stablecoin figures from reported corridor pricing. Bars are illustrative of the sourced ranges, not a live quote.
The speed is the other half. A wire can take one to five business days and stops for weekends and holidays. A stablecoin transfer settles in seconds to minutes, any hour, any day. For a business making payroll across borders, or someone whose family needs the money now, minutes versus days is the whole point. That's why even Western Union started piloting stablecoin rails in 2025 — the incumbents can see it too.
the lessonThe catch nobody advertises: on-ramps and off-ramps
The on-chain transfer is nearly free and instant. The friction moved to the edges — getting in and out of the banking system.
- On-ramp: turning your dollars into a stablecoin. An exchange or app, usually with a fee and an identity check.
- Off-ramp: turning the stablecoin back into spendable local cash on the other end. This is where fees and delays sneak back in, especially in places with thin crypto infrastructure.
- The honest math: "$0.99 to send" is real for the hop, but door-to-door cost depends on both ramps. It's still usually cheaper and faster than the wire. It is not magic-free.
- Volatility isn't the risk here — a dollar token stays a dollar. The risks are the ones from this whole page: the issuer, its bank, and whether you can redeem.
The direction is clear anyway: the middle of the journey went from days-and-percent to seconds-and-cents. The last mile is catching up corridor by corridor.
Takeaway: stablecoins are the first thing crypto built that plainly beats the old system at a job normal people need done. Cheaper and faster than a wire for moving dollars across a border. Just count the ramps, not only the transfer.
The tax line, in one paragraph.
Moving dollars to a dollar stablecoin and back — USD to USDC to USD — generally isn't a taxable event, because you started with a dollar and ended with a dollar and had no gain. But the moment you swap a stablecoin for another crypto (USDC for SOL, USDC for a memecoin), the IRS treats crypto as property and that's a taxable trade, with a gain or loss to track. Same the other way. A stablecoin is a great place to sit; it is not a magic tax-free tunnel between coins.
Go deeper
The full version — every-swap-is-a-sale, staking, wash sales, the on-chain records nobody sends you a form for — is its own lesson. Keep what you make — the tax lesson →
The rules, as they actually stand.
For years stablecoins ran in a gray zone. That changed in 2025. The GENIUS Act — the first federal law aimed squarely at payment stablecoins — was signed on July 18, 2025. Here's what it demands and, just as important, where it actually is in mid-2026, because "there's a law" and "the law is in force" are not the same thing yet.
- 100% reserves, in safe stuff. One dollar of high-quality assets per token: cash, insured bank deposits, and short US Treasury bills (93 days or less), or government money-market funds holding those.
- Monthly disclosure, signed. Reserves attested every month by a PCAOB-registered accounting firm, with the CEO and CFO personally certifying the numbers.
- No yield to holders. Issuers can't pay you interest for holding the stablecoin. (This is aimed straight at the Terra/Anchor playbook.)
- Redeemable on demand, and issuers can't run unrelated businesses with your reserve money.
Verify before you lean on it — status as of mid-2026
The law is passed, but it is not fully in force yet. Through early 2026 the OCC, FDIC, and Treasury's FinCEN each issued proposed rules to implement it, with a public comment window that ran to May 1, 2026. Final regulations are due by July 18, 2026, and full effect is expected around January 2027 (the earlier of 18 months after enactment or 120 days after final rules). So: the framework is real and the direction is set, but the fine print is still being written while you read this. Check the current status before betting on any specific provision.
Takeaway: the rules are moving toward exactly the reserve you'd want anyway — short Treasuries, cash, monthly proof, no funny yield. That's good for the boring fiat-backed coins and fatal for the algorithmic experiments. It just isn't finished. Read the disclosure, not the marketing.
The whole page in five lines
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A stablecoin is a promise to pay you a dollar. Fiat-backed with short Treasuries is the version that has held. Crypto-backed works but can get liquidated. Algorithmic is a graveyard. Even the best one broke for a weekend when its bank failed — so read what backs it, watch the reserves, and count the ramps when you move money.