Four ways a platform loses your bitcoin
Not your keys, not your coins is the conclusion. These are the cases it was drawn from — four failures with four different mechanisms, none of which announced itself in advance, and one of which was Canadian.
The responsibilities that transfer makes an argument: leaving bitcoin with a company means your access depends on things you cannot audit. That is easy to nod along to and hard to feel. This page is the evidence — four collapses, each of which failed in a genuinely different way.
They are worth reading together rather than separately, because the differences are the point. If they had all failed the same way you could learn one warning sign. They did not, and the only thing every customer had in common was that their bitcoin was an entry in someone else's database.
A shuttered shopfront photographed straight on in flat daylight, security grille down, a printed notice taped inside the glass too small to read from the street.
Image to come
1The slow drain nobody could see
Mt. Gox, February 2014. At its height it handled the large majority of global bitcoin trading. When it stopped, roughly 850,000 bitcoin were unaccounted for.
The detail that matters is the timeline. The coins did not vanish in one bad week — the losses accumulated over years, while the exchange continued operating, quoting prices, and showing customers balances that were, by then, fiction. Internal accounting was not good enough to notice, and nothing visible from outside could have told a customer.
What this one demonstrates: a balance on a screen is a claim, not an observation. Your account page renders a number from a company's database. It is not derived from the blockchain, and nothing forces the two to agree.
2The single point of failure who was also a fraud
QuadrigaCX, 2019. Canada's largest bitcoin exchange, and the case closest to home.
The story as it broke was that the founder had died suddenly and taken the only keys with him, stranding roughly 76,000 users. That version is memorable, tidy, and not what happened. The Ontario Securities Commission investigated and concluded the platform had been operating as a fraud — customer funds had been traded on other platforms and lost, and the shortfall long predated the death.
Both readings should worry you, which is why this case earns its place. The generous version is catastrophic key-person risk: one person, no redundancy, no oversight. The accurate version is worse and was invisible in exactly the same way.
What this one demonstrates: "registered" is not "audited", and neither is insurance. Deposits at a Canadian bank are covered by CDIC within limits. Crypto held on a trading platform is not, whatever the marketing implies.
3The yield that made you a creditor
Celsius, Voyager, BlockFi, 2022. None of these was hacked. The coins left through the front door, as lending, and the customers had agreed to it.
The offer was interest on your bitcoin. To pay interest, the platform has to do something with the coins, which means lending them out. That is not custody at all — it is a loan from you to the company. When their borrowers failed and the companies entered bankruptcy, customers discovered what they had actually been holding: an unsecured claim against an insolvent business, queued behind secured creditors.
The terms said so. But "earn 8% on your bitcoin" and "make an unsecured loan to a company whose balance sheet you have never seen" describe the same arrangement, and only one of them was on the marketing.
- Do not read this as "they were honest and customers did not listen". Celsius's founder, Alexander Mashinsky, pleaded guilty to commodities fraud and to manipulating the company's own CEL token, and was sentenced to twelve years in 2025. Prosecutors described him misrepresenting the platform's safety and financial condition, implying regulatory approval the company did not have, and using customer deposits to buy CEL and hold up its price, while selling his own holdings.
- The disclosure and the deception are two separate facts, and both matter. The lending was in the terms; how the business was actually being run was not. A reader who concludes "so I should read the terms more carefully" has taken only half of it.
Which is the harder lesson. The structural risk was real from the first day and readable in the paperwork: you are a creditor, not an owner. Everything else about how those coins were being handled was not, and no amount of careful reading would have surfaced it. Disclosure told you the shape of the risk and nothing about the size of it.
What this one demonstrates: yield is the tell. Bitcoin sitting still does not generate a return. If a platform pays you to hold it there, your coins are not sitting still, and you are being paid for taking a risk that has not been named.
4The house money
FTX, November 2022. The largest and the fastest. A well-regarded exchange, backed by serious investors, with a founder on magazine covers, went from apparently solvent to bankrupt in about a week, with a shortfall in the billions.
Customer deposits had been treated as the company's own money and moved to an affiliated trading firm. There was no hack and no market crash that explains it. The coins customers believed were held for them had been spent.
What this one demonstrates: reputation is not a control. Auditors, investors, regulators in multiple countries and a great many sophisticated customers all looked at FTX and saw a functioning business. Every external signal a careful person could have checked was green.
5What proof of reserves does and does not prove
After 2022 many platforms began publishing proof of reserves, and it is worth knowing precisely what that is worth, because it is regularly presented as though it closes this question.
A proof of reserves demonstrates that the platform controls a certain quantity of bitcoin at a moment in time. That is genuinely something. But solvency is reserves minus liabilities, and the liabilities are the half nobody can see.
- It is a snapshot. Coins can be borrowed for the audit and returned afterwards, which has happened.
- It rarely proves liabilities. Without a verified total of what customers are owed, showing assets proves nothing about whether they are enough.
- It cannot show encumbrance. Coins genuinely held may already be pledged as collateral elsewhere.
- It says nothing about what happens next. Control today is not a commitment about tomorrow.
6What the four have in common
Four different mechanisms — incompetence, fraud, disclosed-but-misunderstood lending, and outright misappropriation. No single warning sign covers them. But the structure underneath was identical every time.
| Case | Mechanism | Visible beforehand? |
|---|---|---|
| Mt. Gox | Losses accumulating unnoticed over years | No — not even internally |
| QuadrigaCX | Fraud, presented as key-person risk | No — it was registered and operating |
| Celsius and others | Customer coins lent out; customers became creditors. At Celsius, also fraud: a guilty plea and a twelve-year sentence | Partly. The lending was in the terms, the rest was not |
| FTX | Deposits spent as company money | No — every external signal was positive |
Note the third row, which is the uncomfortable one in both directions. The arrangement was disclosed, in writing, to everyone, and still took people by surprise, because reading a terms-of-service document is not the same as believing it. And the disclosure covered the structure only. What was being done with the money underneath it came out in a courtroom.
In all four, the customer's bitcoin was a number in a company's database and a liability on its balance sheet. What differed was only how they found out.
7What this argues for, and what it does not
Not that every platform is a fraud. Most are not, most of the time, and this site's comparison of Canadian purchase routes exists because buying bitcoin generally means using one.
What it argues is narrower and firmer: a platform is a place to transact, not a place to keep things. The risk is not that any particular company is dishonest. It is that you cannot tell from outside, that the people who lost money in every case above could not tell either, and that the exposure grows with the balance and the time you leave it there.
- Withdraw after buying, not eventually. The exposure is proportional to the amount and how long it sits there. Getting it off the platform is the step this whole page is arguing for.
- Treat a balance page as a claim. It is a company telling you what it owes you, not evidence of anything on the chain.
- Be suspicious of yield specifically. Of everything above, it is the one failure that announces itself in advance and is still routinely misread.
- Do not read a regulator's registration as protection. Registration sets rules for how a business must operate. It is not deposit insurance and it did not prevent any of these.
The short version
Mt. Gox bled coins for years without anyone noticing. Quadriga was a fraud wearing the costume of a tragedy. Celsius disclosed the lending, concealed the rest, and its founder is serving twelve years. FTX simply spent the deposits. Different mechanisms, different warning signs, and one structure in common: the bitcoin belonged to the company and the customer held a promise.
If you take one thing from this page
Every customer in every case above believed their balance was their bitcoin. The number on the screen was accurate right up until the moment it was not, and there was no way to check from outside. Holding your own keys replaces that promise with something you can verify yourself — which is the entire trade, and the reason it is worth the work.
Figures here are the widely reported ones and are deliberately approximate; bankruptcy claims, recovered amounts and final accounting have moved for several of these cases and in some are still moving. The mechanisms are the durable part and are what this page is for. For the Canadian case, the Ontario Securities Commission's own published investigation is the primary account; for Celsius, the guilty plea and the twelve-year sentence handed down in May 2025 are a matter of public record in the Southern District of New York.