🏛️ The Mt. Gox Hack

Still being paid out

The most expensive lesson in Bitcoin's history is still being paid out — more than a decade later.

Rise of an exchange

Mt. Gox launched as a bitcoin exchange in 2010 and quickly became the world's dominant venue, at one point handling the large majority of all bitcoin trading activity.

If you bought bitcoin in those years, there's a good chance you bought it there.

The collapse

Over time, hundreds of thousands of bitcoin were stolen from the exchange through a series of security failures — quietly, over years, while it kept operating.

In February 2014, Mt. Gox halted withdrawals and collapsed, filing for bankruptcy after disclosing the loss of roughly 850,000 BTC.

(About 200,000 were later located in an old wallet. The rest were gone.)

Whose bitcoin was it, really?

Mt. Gox users didn't hold their own private keys — the exchange did.

Their balance was a number in a company's database: a claim, not a coin.

When it failed, their bitcoin wasn't just at risk. For years, it was simply gone.

Still unresolved today

The rehabilitation process to repay creditors is still ongoing.

As of late 2025, the court-appointed trustee had extended the final repayment deadline to October 2026 — over twelve years after the collapse.

Twelve years of waiting on a company to give back what was supposedly yours the whole time.

Why it matters

This is "not your keys, not your coins" playing out in the real world, at massive scale — the clearest historical case for self-custody there is.

Funds held by a third party are only ever as safe as that third party's security and its solvency.

You don't get to audit either one.

Try it: Whose bitcoin is it?

Split your stack between an exchange and your own custody — then fail the exchange.

Slide how much you leave on an exchange versus hold yourself, then watch the exchange collapse. One half becomes a bankruptcy claim; the other never notices. This is "not your keys, not your coins" as arithmetic. Open the Whose Bitcoin Is It? tool →

Quick check: Roughly how much bitcoin did Mt. Gox lose?

1. Around 850,000 BTC ✓
2. Around 21,000 BTC
3. Around 10 million BTC

Roughly 4% of all bitcoin that will ever exist, taken from a single company that thousands of people had trusted.

Quick check: Why couldn't Mt. Gox users simply move their funds when trouble started?

1. The Bitcoin network was down
2. They didn't hold the private keys — the exchange did ✓
3. Their transactions were blocked by regulators

Withdrawals were a feature the company chose to offer — and then chose to stop offering. Keys are the only thing that isn't somebody's decision.

Next up

Bitcoin survived its internal fights and its most infamous exchange collapse.

Then, slowly, the world's largest institutions started paying attention.