What Happens When a Stablecoin Shuts Down? Two Deadlines

What happens when a stablecoin shuts down looks nothing like a crash if the issuer is closing on purpose. On Monday 26 October, 57% of all the GYEN in existence left one wallet in three transfers, and ninety-two minutes after the first those tokens were burned. GYEN is a yen stablecoin; Etherscan labels the wallet Coinbase 10. Nobody ran, and nobody has alleged a shortfall. For five months before that, the issuer had been paying full value to any account holder who asked, and the supply had fallen about 11%.

So five months of choosing moved 120 million tokens, and what looks like one exchange's default moved 533 million in an afternoon.

What happens when a stablecoin shuts down?

The issuer stops minting, pays par to account holders until a deadline, then pushes what it still owes to the wallets it can clear. GMO-Z.com Trust, the New York trust company behind GYEN and its dollar sibling ZUSD, began a voluntary dissolution on 15 May and hasn't said why. Par means ¥1 a GYEN or $1 a ZUSD, and that window shuts just before midnight Eastern on 11 November. After that comes a Mandatory Redemption, in plain terms a sweep. Each cleared wallet gets USDC of equal value, "expected" by the end of 2026.

An exchange can run its own date ahead of all that. Coinbase stopped GYEN transfers that Monday, sixteen days before the issuer's deadline, and converted what customers had left into USDC. One token, then, comes with several defaults, several answers to doing nothing.

Which one you get depends on where the token sits.

Liquidity pools were Tao's first market, and he still believes a pool's price over anyone's account of it. He has 40,000 GYEN left from an old experiment, about $254. On the morning of 30 October, CoinGecko prices the token at ¥0.905 against the issuer's ¥1, and he sits down at the table pleased with himself. "That's nearly 10% for whoever buys it and redeems it. With a balance like mine, you hit the pool, take what it gives you and stop thinking."

Soren spent decades in the rooms where failed trades get unwound. He came out with a low opinion of any plan that needs the customer to act on time. On an exchange, he points out, Tao would have done nothing, paid no gas and been finished by the 29th. "You're not on one, so sell and get a receipt. Wallets have a long list of ways to be stopped."

Lilith ran security teams for twenty years before she took up art, and she still counts how many parties can move your money without asking you. GMO's terms bind anyone holding the coin, "whether or not they are Account Holders". So a wallet that passes its screen collects full value for doing nothing, and in public. "Sit still. On an exchange you'd get its number and be told that was the market."

The ruling falls to Lucia, whose subject is what a crowd actually does with its money, not what anyone says about it. First she asks Tao how much money was behind his ¥0.905.

What did each default pay?

Tao hunts for the volume while Lilith lays out the paper. One GYEN is one yen, converted at a single rate set on 12 November, and "the same exchange rate applies to every holder". Anyone can check that against a neighbor's wallet. Coinbase promised something else, "the market rate at the time of conversion". "Which market? Its own API lists GYEN-USD as delisted. That's a market rate from a market it closed," Lilith says.

"Nobody has to take its word, or yours. Look at the chain," Soren says, and the trail is short. Three transfers moved 533,502,293 GYEN out of the Coinbase wallet to a second wallet. That one has been sending GYEN for years to a burn contract, created by an address Etherscan labels GMO-Z.com: Deployer. The lot reached the contract within half an hour of the last transfer and was gone half an hour after that. The next afternoon, $3,379,805.47 in USDC reached Coinbase's wallet through it.

"That's $0.006335 a token, within a quarter of a percent of ¥1 at either day's European Central Bank rate. It's no discount." Neither firm has said the money paid for that lot, so that much is his inference, from the timing and from who touched both sides.

"That's a wallet's receipt, and the lot may not even be all customers' tokens. I'm asking what an account got," Lilith says.

"It should have published the rate. Good settlement notices never leave the price to a phrase. But USDC received over GYEN held is one line of arithmetic, and every account has both numbers."

Tao has his volume now: ninety-three dollars in a day. "Refresh it," Lucia says, and the page now shows ¥0.976. A little before two o'clock UTC, one wallet sold about $350 of GYEN through a routing app, and the page jumped with it. The pool paid about ¥0.993 a token, and the app's fees cut that to ¥0.983.

"I took this for panic too, the first time," she says. "It sat near ¥0.90 the morning Coinbase cut transfers, on about fifteen dollars of volume. On 17 October it said ¥1.058, above par, on sixty dollars. Fear comes with volume. That isn't panic, it's somebody clearing out a drawer." GMO warned of this in May: aggregator prices "may display values materially above or below par". She looks back at Tao. "You said you believe pools, and then you quoted a page."

"I did," he says, and he leaves the page for the pool. The second wallet's buys from it since late September all cost within a percent of par, so that gap was never there to buy. Seventy-eight minutes after that small sale, it bought nearly the same amount back.

"The gap on that screen had no money behind it, and the one lot anyone can see came to about ¥1," Lucia says. "Each account's number is missing, and only that customer can supply it. I can't find a price gap here worth a debate."

That second wallet is what a peg looks like up close. A peg is not a feature of the coin but the work of somebody able to reach the issuer at all. That somebody buys below the promise and carries the tokens back. Everyone else's price is borrowed from that access, which is easy to forget until the issuer names a last day.

"If everything pays about a yen, what are you two still arguing about?" Tao asks.

What can stop a stablecoin redemption?

"Everything between a holder and that yen," Soren says, and he has GMO's own list. GMO decides whether a wallet passes, one at a time, on "an anti-money laundering and operational-risk assessment". Where that screen can't be completed, it "will not deliver USDC". Pass it and you can still miss. A balance under the chain's minimum USDC transfer isn't processed. A Stellar account needs a USDC trustline, an opt-in to hold the asset, which "GMO Trust cannot establish" for you. Tokens bridged to a chain GMO doesn't support get nothing, so their owner has to leave the way they came in first. When delivery fails, the amount "will be retained and subsequently addressed in accordance with applicable law", and any recourse "will be described in a separate notice".

"That notice doesn't exist yet. A wallet balance was always something the issuer could act on, and a closure only makes it write the procedure down." The terms add that tokens in a wallet it can't clear "may be frozen or burned", and that your "only recourse" may run through NYDFS, the New York regulator. "And you told him to sit still on these," he says to Lilith. Its wind-down section reserves the right, "in our sole discretion", to change the timing and the exchange-rate method. It can even run the wind-down "on a differentiated basis", including by whether you hold an account.

"That list is worse than you made it sound, and every item on it is one only a self-custodian can hit. Nobody on Coinbase ever needed a trustline. For someone who can't run a wallet I have no answer, and I've had twenty years to find one."

She isn't finished, though. In November 2023 Binance said that on New Year's Eve BUSD balances would become another company's coin, FDUSD, one for one. Customers in Japan, France, Italy, Poland and Kazakhstan were left out. Coinbase's version, three years on, was USDC at no stated rate. "A venue's default isn't a rule, it's whatever that venue decided that year."

"Decided, announced and finished in days. A customer in Italy at least had an account and someone to write to. Tell me who a stopped wallet writes to," Soren says. GMO's notice hands him one more line: it "will never ask you to connect a Wallet, sign a transaction, or pay a fee". "Somebody wrote that because somebody will ask. Nobody phishes a conversion that has already happened."

"To nobody, until that notice exists," Lilith says.

"This one is Soren's. Every written way of being stopped short of payment is on the wallet side. A list in the issuer's own words can't be argued away," Lucia says. As of 30 October, 401 million GYEN, about $2.5 million, still sits in about 12,000 addresses on Ethereum and Stellar, twelve days from the deadline. "Those are the people that list is about," she says, and the page telling them what happens if they're stopped hasn't been written.

A key decides who can move a token, and it has never decided who has to pay for it.

Whose clock runs out first?

"So next time I leave it on the exchange and let the exchange worry," Tao says.

"Then you've left it the calendar as well," Lilith says. Coinbase posted its dates on 20 October, though Crypto Briefing had reported the plan by 11 September. The pattern is familiar from any delisting, where a venue retires its own exposure first. From the 26th a customer couldn't move the token at all. GMO's par window stayed open sixteen more days, shut to anyone still on the platform. "Tax consequences may apply", the notice adds, and if they do, they arrive on a date the customer didn't pick. The sweep's arithmetic, she says, is public: one rate for everyone means you can check your USDC against anyone else's on-chain.

"A rate from 'such pricing sources as GMO Trust shall select'. Fine, one rate. Now the wait," Soren says. Coinbase's conversion sits on its status page as an incident, opened on the 20th and closed on the 29th. The closing words are "This incident has been resolved", a modest send-off for something people held as money. Conversion began on the 26th, so that's three days. The sweep is only "expected" by year-end, on a date GMO "will not disclose in advance". And par has its own price, he says. The wire comes with "any associated FX or wire fees charged by your bank or intermediary banks", and that bank "may reject the transfer".

Tao works it on his own balance. That seller's ¥0.983 would leave him about $4 short of par, before gas. Suppose his bank takes $25 to receive a foreign wire, his guess and no bank's quote. He would pay about six times the discount to avoid it. At that fee, the wire only starts to win at a balance of about $1,500.

Par is free at the issuer and priced at your bank.

"You're saying the best price I can get is for doing nothing," Tao says, and he doesn't sound sure he likes it. Lilith told him so when he sat down. "If you clear a screen you can't see, on a date you can't know," Soren says.

"The date is set by whoever holds the token, so on who owns the clock Lilith is right," Lucia says. "A customer's choice ended on the 26th, whatever GMO's notice said. On who gets paid first Soren is right, by up to two months. And on a balance like Tao's, the bank can eat the whole gap between par and the pool."

Whose default do you want when the notice comes?

"Put it in one place for me. Wherever the token is, if I do nothing, what happens, who sets the number, and what can stop it?" Tao asks.

"If you can run a wallet on a supported chain and you want the issuer's terms, your deadline is the venue's date, not the issuer's. If you can't, the venue's default is the one to want, and you should know you're taking its number on trust," Lucia says.

So far, price has decided nothing in this closure.

She won't rule on what each Coinbase account received or what becomes of a stopped wallet. The two documents that would settle them, a per-account rate and GMO's recourse notice, aren't public.

"I came in with ¥0.905 and a plan. There was ninety-three dollars behind that number, and 533 million tokens went for about ¥1 on a day it said ¥0.90. I still believe the pool, but I quoted a page instead. What I'm choosing between isn't a price, it's a wait, a screen and a bank," Tao says. Half his balance goes to the pool this week, because he wants to see the fill with his own fees on it. The other half stays, so he can learn what "expected" means.

What the next notice has to say

Either missing document could undo a ruling, and Soren and Lilith are exposed to different ones. "Let enough customers post their statements. If the USDC comes in well under that lot's $0.0063 a token, the quiet default was quietly expensive, and I'd stop recommending it," Soren says. Lilith's worry sits in the recourse notice GMO has promised. "If a stopped wallet has to spend years chasing a regulator, or the sweep leaves ordinary wallets behind in any number, I'd stop sending small holders to their own keys," she says.

If you still hold GYEN, or ZUSD on the same dates at $1, and the deadline hasn't passed, the date that counts is the day the tokens arrive. A redemption request whose tokens land after the deadline is cancelled. GMO asks you to allow time for KYC, and your bank may refuse a yen wire, so start both now. On Stellar you need that USDC trustline in place, and tokens on an unsupported chain have to come back or be swapped first. You can ignore the stranger offering to help you claim USDC, because GMO says it will never ask.

Any token left on-chain after its wallet is paid "carries no entitlement against GMO Trust". Until GMO removes them, those balances will still show in wallets, and some page will probably go on quoting them a price, to several decimal places, on about fifteen dollars of volume.

Sell half of a small position at market in the simulator and study the fill on the ticket. Leave the other half behind a limit just above the quote and come back in a week. There's no issuer and no redemption in there, only paper money and the choice GYEN holders had: a price now, or a better number later with a wait attached. Which half would you want to be holding if the wait had no date on it?

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