A balance is not bitcoin.
Keys are.
When you leave bitcoin on an exchange, the exchange holds the private keys. You hold a balance in their accounting system, a record of what they owe you, not direct control over the on-chain bitcoin itself. The distinction only becomes visible when something goes wrong.
The largest exchange in the world. Customers had no warning.
In 2014, Mt. Gox, then handling the majority of all global Bitcoin trading volume, collapsed. Approximately 850,000 bitcoin belonging to customers had gone missing since 2011. The loss was invisible because customers trusted the exchange to hold their keys.| Exchange custody | Self-custody | |
|---|---|---|
| Private keys | Exchange holds them | You hold them |
| Withdrawal | Requires platform approval | Immediate, permissionless |
| Platform failure risk | Full exposure | None |
| Account freeze risk | Yes, exchange or regulator | None |
| What you own | A claim on the platform | The bitcoin itself |
Not your keys, not your coins. That principle is true, but it is also not a deadline. For a small amount while you are learning, a reputable exchange is a reasonable starting point. The goal is an informed choice, not immediate action.
From the book
This myth is one chapter of Reasonable Doubt.
All twenty myths from this series, revised and rechecked, in one book you can read start to finish or hand to the skeptic in your life. Same standard as the site: the strongest version of each objection, the evidence, and a verdict that goes no further than the evidence does.
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